

A001316


Gould's sequence: a(n) = Sum_{k=0..n} (binomial(n,k) mod 2); number of odd entries in row n of Pascal's triangle (A007318); a(n) = 2^A000120(n).
(Formerly M0297 N0109)


189



1, 2, 2, 4, 2, 4, 4, 8, 2, 4, 4, 8, 4, 8, 8, 16, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 4, 8, 8, 16, 8, 16, 16, 32, 8, 16, 16, 32, 16, 32, 32, 64, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 4, 8, 8, 16, 8, 16, 16, 32
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OFFSET

0,2


COMMENTS

Also called Dress's sequence.
This sequence might be better called Glaisher's sequence, since James Glaisher showed that odd binomial coefficients are counted by 2^A000120(n) in 1899.  Eric Rowland, Mar 17 2017 [However, the name "Gould's sequence" is deeply entrenched in the literature.  N. J. A. Sloane, Mar 17 2017] [Named after the American mathematician Henry Wadsworth Gould (b. 1928).  Amiram Eldar, Jun 19 2021]
All terms are powers of 2. The first occurrence of 2^k is at n = 2^k  1; e.g., the first occurrence of 16 is at n = 15.  Robert G. Wilson v, Dec 06 2000
a(n) is the highest power of 2 dividing binomial(2n,n) = A000984(n).  Benoit Cloitre, Jan 23 2002
Also number of 1's in nth row of triangle in A070886.  Hans Havermann, May 26 2002. Equivalently, number of live cells in generation n of a onedimensional cellular automaton, Rule 90, starting with a single live cell.  Ben Branman, Feb 28 2009. Ditto for Rule 18.  N. J. A. Sloane, Aug 09 2014. This is also the oddrule cellular automaton defined by OddRule 003 (see EkhadSloaneZeilberger "OddRule Cellular Automata on the Square Grid" link).  N. J. A. Sloane, Feb 25 2015
Also number of numbers k, 0<=k<=n, such that (k OR n) = n (bitwise logical OR): a(n) = #{k : T(n,k)=n, 0<=k<=n}, where T is defined as in A080098.  Reinhard Zumkeller, Jan 28 2003
To construct the sequence, start with 1 and use the rule: If k >= 0 and a(0),a(1),...,a(2^k1) are the first 2^k terms, then the next 2^k terms are 2*a(0),2*a(1),...,2*a(2^k1).  Benoit Cloitre, Jan 30 2003
Also, numerator((2^k)/k!).  Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Mar 03 2004
The odd entries in Pascal's triangle form the Sierpiński Gasket (a fractal).  Amarnath Murthy, Nov 20 2004
Row sums of Sierpiński's Gasket A047999.  Johannes W. Meijer, Jun 05 2011
Fixed point of the morphism "1" > "1,2", "2" > "2,4", "4" > "4,8", ..., "2^k" > "2^k,2^(k+1)", ... starting with a(0) = 1; 1 > 12 > 1224 > = 12242448 > 122424482448488(16) > ... .  Philippe Deléham, Jun 18 2005
a(n) = number of 1's of stage n of the onedimensional cellular automaton with Rule 90.  Andras Erszegi (erszegi.andras(AT)chello.hu), Apr 01 2006
a(33)..a(63) = A117973(1)..A117973(31).  Stephen Crowley, Mar 21 2007
Or the number of solutions of the equation: A000120(x) + A000120(nx) = A000120(n).  Vladimir Shevelev, Jul 19 2009
For positive n, a(n) equals the denominator of the permanent of the n X n matrix consisting entirely of (1/2)'s.  John M. Campbell, May 26 2011
Companions to A001316 are A048896, A105321, A117973, A151930 and A191488. They all have the same structure. We observe that for all these sequences a((2*n+1)*2^p1) = C(p)*A001316(n), p >= 0. If C(p) = 2^p then a(n) = A001316(n), if C(p) = 1 then a(n) = A048896(n), if C(p) = 2^p+2 then a(n) = A105321(n+1), if C(p) = 2^(p+1) then a(n) = A117973(n), if C(p) = 2^p2 then a(n) = (1)*A151930(n) and if C(p) = 2^(p+1)+2 then a(n) = A191488(n). Furthermore for all a(2^p  1) = C(p).  Johannes W. Meijer, Jun 05 2011
a(n) = number of zeros in nth row of A219463 = number of ones in nth row of A047999.  Reinhard Zumkeller, Nov 30 2012
This is the Run Length Transform of S(n) = {1,2,4,8,16,...} (cf. A000079). The Run Length Transform of a sequence {S(n), n>=0} is defined to be the sequence {T(n), n>=0} given by T(n) = Product_i S(i), where i runs through the lengths of runs of 1's in the binary expansion of n. E.g., 19 is 10011 in binary, which has two runs of 1's, of lengths 1 and 2. So T(19) = S(1)*S(2). T(0)=1 (the empty product).  N. J. A. Sloane, Sep 05 2014
A105321(n+1) = a(n+1) + a(n).  Reinhard Zumkeller, Nov 14 2014
a(n) = A261363(n,n) = number of distinct terms in row n of A261363 = number of odd terms in row n+1 of A261363.  Reinhard Zumkeller, Aug 16 2015
From Gary W. Adamson, Aug 26 2016: (Start)
A production matrix for the sequence is lim_{k>infinity} M^k, the leftshifted vector of M:
1, 0, 0, 0, 0, ...
2, 0, 0, 0, 0, ...
0, 1, 0, 0, 0, ...
0, 2, 0, 0, 0, ...
0, 0, 1, 0, 0, ...
0, 0, 2, 0, 0, ...
0, 0, 0, 1, 0, ...
...
The result is equivalent to the g.f. of Apr 06 2003: Product_{k>=0} (1 + 2*z^(2^k)). (End)
Number of binary palindromes of length n for which the first floor(n/2) symbols are themselves a palindrome (Ji and Wilf 2008).  Jeffrey Shallit, Jun 15 2017


REFERENCES

Arthur T. Benjamin and Jennifer J. Quinn, Proofs that really count: the art of combinatorial proof, M.A.A., 2003, p. 75ff.
Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 145151.
James W. L. Glaisher, On the residue of a binomialtheorem coefficient with respect to a prime modulus, Quarterly Journal of Pure and Applied Mathematics, Vol. 30 (1899), pp. 150156.
H. W. Gould, Exponential Binomial Coefficient Series. Tech. Rep. 4, Math. Dept., West Virginia Univ., Morgantown, WV, Sep 1961.
Olivier Martin, Andrew M. Odlyzko and Stephen Wolfram, Algebraic properties of cellular automata, Comm. Math. Physics, Vol. 93 (1984), pp. 219258. Reprinted in Theory and Applications of Cellular Automata, S Wolfram, Ed., World Scientific, 1986, pp. 5190 and in Cellular Automata and Complexity: Collected Papers of Stephen Wolfram, AddisonWesley, 1994, pp. 71113
Manfred R. Schroeder, Fractals, Chaos, Power Laws, W. H. Freeman, NY, 1991, page 383.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Andrew Wuensche, Exploring Discrete Dynamics, Luniver Press, 2011. See Fig. 2.3.


LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..50000 (terms 0..1000 from T. D. Noe)
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), pp. 157191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n1)1) for n >= 2.]
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS.
JeanPaul Allouche and Jeffrey Shallit, The ring of kregular sequences, Theoretical Computer Sci., Vol. 98 (1992), pp. 163197.
Paul Barry, A Note on Riordan Arrays with Catalan Halves, arXiv:1912.01124 [math.CO], 2019.
George Beck and Karl Dilcher, A Matrix Related to Stern Polynomials and the ProuhetThueMorse Sequence, arXiv:2106.10400 [math.CO], 2021.
Neil J. Calkin, Eunice Y. S. Chan, and Robert M. Corless, Some Facts and Conjectures about Mandelbrot Polynomials, Maple Transactions (2021) Vol. 1, No. 1, Article 1.
Neil J. Calkin, Eunice Y. S. Chan, Robert M. Corless, David J. Jeffrey, and Piers W. Lawrence, A Fractal Eigenvector, arXiv:2104.01116 [math.DS], 2021.
Emeric Deutsch and Bruce E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, arXiv:math/0407326 [math.CO], 2004.
Emeric Deutsch and Bruce E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, J. Num. Theory, Vol. 117 (2006), pp. 191215.
Philippe Dumas, Diviser pour regner Comportement asymptotique. [Broken Link]
Philippe Dumas, Diviser pour regner Comportement asymptotique. (has many references)
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, A MetaAlgorithm for Creating Fast Algorithms for Counting ON Cells in OddRule Cellular Automata, arXiv:1503.01796 [math.CO], 2015; see also the Accompanying Maple Package.
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, OddRule Cellular Automata on the Square Grid, arXiv:1503.04249 [math.CO], 2015.
Steven R. Finch, StolarskyHarborth Constant. [Broken link]
Steven R. Finch, StolarskyHarborth Constant. [From the Wayback machine]
Michael Gilleland, Some SelfSimilar Integer Sequences.
Kathy Q. Ji and Herbert S. Wilf, Extreme Palindromes, Amer. Math. Monthly, Vol. 115, No. 5 (2008), pp. 447451.
Alan J. Macfarlane, Generating functions for integer sequences defined by the evolution of cellular automata....
Sam Northshield, Stern's Diatomic Sequence 0,1,1,2,1,3,2,3,1,4,..., Amer. Math. Month., Vol. 117, No. 7 (2010), pp. 581598.
Tomaz Pisanski and Thomas W. Tucker, Growth in Repeated Truncations of Maps, Atti Sem. Mat. Fis. Univ. Modena, Vol. 49 (2001), suppl., pp. 167176.
David G. Poole, The towers and triangles of Professor Claus (or, Pascal knows Hanoi), Math. Mag., Vol. 67, No. 5 (1994), pp. 323344.
N. J. A. Sloane, Illustration of first 20 generations of Rule 90.
N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168 [math.CO], 2015.
Lukas Spiegelhofer and Michael Wallner, Divisibility of binomial coefficients by powers of two, arXiv:1710.10884 [math.NT], 2017.
Ralf Stephan, Divideandconquer generating functions. I. Elementary sequences, arXiv:math/0307027 [math.CO], 2003.
Eric Weisstein's World of Mathematics, Elementary Cellular Automaton.
Stephen Wolfram, Statistical mechanics of cellular automata, Rev. Mod. Phys., Vol. 55 (1983), pp. 601644.
Stephen Wolfram, Geometry of Binomial Coefficients, Amer. Math. Monthly, Vol. 91, No. 9 (November 1984), pp. 566571.
Chai Wah Wu, Sums of products of binomial coefficients mod 2 and run length transforms of sequences, arXiv preprint arXiv:1610.06166 [math.CO], 2016.
Zhujun Zhang, A Note on Counting Binomial Heaps, ResearchGate (2019).
Index entries for sequences related to cellular automata
Index entries for sequences that are fixed points of mappings
Index entries for sequences computed with run length transform


FORMULA

a(n) = 2^A000120(n).
a(0) = 1; for n > 0, write n = 2^i + j where 0 <= j < 2^i; then a(n) = 2*a(j).
a(n) = 2*a(n1)/A006519(n) = A000079(n)*A049606(n)/A000142(n).
a(n) = A038573(n) + 1.
G.f.: Product_{k>=0} (1+2*z^(2^k)).  Ralf Stephan, Apr 06 2003
a(n) = Sum_{i=0..2*n} (binomial(2*n, i) mod 2)*(1)^i.  Benoit Cloitre, Nov 16 2003
a(n) mod 3 = A001285(n).  Benoit Cloitre, May 09 2004
a(n) = 2^n  2*Sum_{k=0..n} floor(binomial(n, k)/2).  Paul Barry, Dec 24 2004
a(n) = Product_{k=0..log_2(n)} 2^b(n, k), b(n, k) = coefficient of 2^k in binary expansion of n.  Paul D. Hanna
Sum_{k=0..n1} a(k) = A006046(n).
a(n) = n/2 + 1/2 + (1/2)*Sum_{k=0..n} ((1)^binomial(n,k)).  Stephen Crowley, Mar 21 2007
G.f. for a(n)/A156769(n): (1/2)*z^(1/2)*sinh(2*z^(1/2)).  Johannes W. Meijer, Feb 20 2009
Equals infinite convolution product of [1,2,0,0,0,0,0,0,0] aerated (A000079  1) times, i.e., [1,2,0,0,0,0,0,0,0] * [1,0,2,0,0,0,0,0,0] * [1,0,0,0,2,0,0,0,0].  Mats Granvik, Gary W. Adamson, Oct 02 2009
a(n) = f(n, 1) with f(x, y) = if x = 0 then y otherwise f(floor(x/2), y*(1 + x mod 2)).  Reinhard Zumkeller, Nov 21 2009
a(n) = 2^(number of 1's in binary form of (n1)).  Gabriel C. Benamy, Dec 08 2009
a((2*n+1)*2^p1) = (2^p)*a(n), p >= 0.  Johannes W. Meijer, Jun 05 2011
a(n) = A000120(A001317(n)).  Reinhard Zumkeller, Nov 24 2012
a(n) = A226078(n,1).  Reinhard Zumkeller, May 25 2013
a(n) = lcm(n!, 2^n) / n!.  Daniel Suteu, Apr 28 2017
a(n) = A061142(A005940(1+n)).  Antti Karttunen, May 29 2017


EXAMPLE

Has a natural structure as a triangle:
.1,
.2,
.2,4,
.2,4,4,8,
.2,4,4,8,4,8,8,16,
.2,4,4,8,4,8,8,16,4,8,8,16,8,16,16,32,
.2,4,4,8,4,8,8,16,4,8,8,16,8,16,16,32,4,8,8,16,8,16,16,32,8,16,16,32,16,32,32,64,
....
The rows converge to A117973.
From Omar E. Pol, Jun 07 2009: (Start)
Also, triangle begins:
.1;
.2,2;
.4,2,4,4;
.8,2,4,4,8,4,8,8;
16,2,4,4,8,4,8,8,16,4,8,8,16,8,16,16;
32,2,4,4,8,4,8,8,16,4,8,8,16,8,16,16,32,4,8,8,16,8,16,16,32,8,16,16,32,16,32,32;
64,2,4,4,8,4,8,8,16,4,8,8,16,8,16,16,32,4,8,8,16,8,16,16,32,8,16,16,32,16,32,...
(End)
G.f. = 1 + 2*x + 2*x^2 + 4*x^3 + 2*x^4 + 4*x^5 + 4*x^6 + 8*x^7 + 2*x^8 + ...


MAPLE

A001316 := proc(n) local k; add(binomial(n, k) mod 2, k=0..n); end;
S:=[1]; S:=[op(S), op(2*s)]; # repeat ad infinitum!
a := n > 2^add(i, i=convert(n, base, 2)); # Peter Luschny, Mar 11 2009


MATHEMATICA

Table[ Sum[ Mod[ Binomial[n, k], 2], {k, 0, n} ], {n, 0, 100} ]
Nest[ Join[#, 2#] &, {1}, 7] (* Robert G. Wilson v, Jan 24 2006 and modified Jul 27 2014 *)
Map[Function[Apply[Plus, Flatten[ #1]]], CellularAutomaton[90, {{1}, 0}, 100]] (* Produces counts of ON cells. N. J. A. Sloane, Aug 10 2009 *)
ArrayPlot[CellularAutomaton[90, {{1}, 0}, 20]] (* Illustration of first 20 generations.  N. J. A. Sloane, Aug 14 2014 *)
Table[2^(RealDigits[n  1, 2][[1]] // Total), {n, 1, 100}] (* Gabriel C. Benamy, Dec 08 2009 *)
CoefficientList[Series[Exp[2*x], {x, 0, 100}], x] // Numerator (* JeanFrançois Alcover, Oct 25 2013 *)
Count[#, _?OddQ]&/@Table[Binomial[n, k], {n, 0, 90}, {k, 0, n}] (* Harvey P. Dale, Sep 22 2015 *)


PROG

(PARI) {a(n) = if( n<0, 0, numerator(2^n / n!))};
(PARI) A001316(n)=1<<norml2(binary(n)) \\ M. F. Hasler, May 03 2009
(PARI) a(n)=2^hammingweight(n) \\ Charles R Greathouse IV, Jan 04 2013
(Haskell)
import Data.List (transpose)
a001316 = sum . a047999_row  Reinhard Zumkeller, Nov 24 2012
a001316_list = 1 : zs where
zs = 2 : (concat $ transpose [zs, map (* 2) zs])
 Reinhard Zumkeller, Aug 27 2014, Sep 16 2011
(Sage)
def A001316(n):
if n <= 1: return Integer(n+1)
return A001316(n//2) << n%2
[A001316(n) for n in range(88)] # Peter Luschny, Nov 19 2012
(Python)
def A001316(n):
return 2**bin(n)[2:].count("1") # Indranil Ghosh, Feb 06 2017
(Scheme) (define (A001316 n) (let loop ((n n) (z 1)) (cond ((zero? n) z) ((even? n) (loop (/ n 2) z)) (else (loop (/ ( n 1) 2) (* z 2)))))) ;; Antti Karttunen, May 29 2017


CROSSREFS

Equals left border of triangle A166548.  Gary W. Adamson, Oct 16 2009
For generating functions Product_{k>=0} (1+a*x^(b^k)) for the following values of (a,b) see: (1,2) A000012 and A000027, (1,3) A039966 and A005836, (1,4) A151666 and A000695, (1,5) A151667 and A033042, (2,2) A001316, (2,3) A151668, (2,4) A151669, (2,5) A151670, (3,2) A048883, (3,3) A117940, (3,4) A151665, (3,5) A151671, (4,2) A102376, (4,3) A151672, (4,4) A151673, (4,5) A151674.
For partial sums see A006046. For first differences see A151930.
This is the numerator of 2^n/n!, while A049606 gives the denominator.
Cf. A051638, A048967, A007318, A094959, A048896, A117973, A008977, A139541, A048883, A102376, A038573, A159913, A000079, A166548, A006047, A089898, A105321, A061142.
Cf. A047999, A261363, A261366.
If we subtract 1 from the terms we get a pair of essentially identical sequences, A038573 and A159913.
A163000 and A163577 count binomial coefficients with 2adic valuation 1 and 2. A275012 gives a measure of complexity of these sequences.  Eric Rowland, Mar 15 2017
Cf. A286575 (runlength transform of this sequence), also A037445.
Sequence in context: A157227 A054536 A293664 * A285741 A161831 A096865
Adjacent sequences: A001313 A001314 A001315 * A001317 A001318 A001319


KEYWORD

nonn,easy,nice


AUTHOR

N. J. A. Sloane


EXTENSIONS

Additional comments from Henry Bottomley, Mar 12 2001
Further comments from N. J. A. Sloane, May 30 2009


STATUS

approved



