

A000332


Binomial coefficient binomial(n,4) = n*(n1)*(n2)*(n3)/24.
(Formerly M3853 N1578)


270



0, 0, 0, 0, 1, 5, 15, 35, 70, 126, 210, 330, 495, 715, 1001, 1365, 1820, 2380, 3060, 3876, 4845, 5985, 7315, 8855, 10626, 12650, 14950, 17550, 20475, 23751, 27405, 31465, 35960, 40920, 46376, 52360, 58905, 66045, 73815, 82251, 91390, 101270, 111930, 123410
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,6


COMMENTS

Number of intersection points of diagonals of convex ngon where no more than two diagonals intersect at any point in the interior.
Also the number of equilateral triangles with vertices in an equilateral triangular array of points with n rows (offset 1), with any orientation.  Ignacio Larrosa Cañestro, Apr 09 2002
Start from cubane and attach amino acids according to the reaction scheme that describes the reaction between the active sites. See the hyperlink on chemistry.  Robert G. Wilson v, Aug 02 2002
For n>0 a(n)=(1/8)*coefficient of x in Zagier's polynomial P_(2n,n). (Zagier's polynomials are used by parigp for acceleration of alternating or positive series.)
Figurate numbers based on the 4dimensional regular convex polytope called the regular 4simplex, pentachoron, 5cell, pentatope or 4hypertetrahedron with Schlaefli symbol {3,3,3}. a(n)=((n*(n1)*(n2)*(n3))/4!).  Michael J. Welch (mjw1(AT)ntlworld.com), Apr 01 2004, R. J. Mathar, Jul 07 2009
a(n) = A110555(n+1,4).  Reinhard Zumkeller, Jul 27 2005
Maximal number of crossings that can be created by connecting n vertices with straight lines.  Cameron RedsellMontgomerie (credsell(AT)uoguelph.ca), Jan 30 2007
If X is an nset and Y a fixed (n1)subset of X then a(n) is equal to the number of 4subsets of X intersecting Y.  Milan Janjic, Aug 15 2007
Product of four consecutive numbers divided by 24.  Artur Jasinski, Dec 02 2007
Only prime in this sequence is 5.  Artur Jasinski, Dec 02 2007
For strings consisting entirely of 0s and 1s, the number of distinct arrangements of four 1s such that 1s are not adjacent. The shortest possible string is 7 characters, of which there is only one solution: 1010101, corresponding to a(5). An eightcharacter string has 5 solutions, nine has 15, ten has 35 and so on, congruent to A000332.  Gil Broussard, Mar 19 2008
For a(n)>0, a(n) is pentagonal if and only if 3 does not divide n. All terms belong to the generalized pentagonal sequence (A001318). Cf. A000326, A145919, A145920.  Matthew Vandermast, Oct 28 2008
Nonzero terms = row sums of triangle A158824.  Gary W. Adamson, Mar 28 2009
Except for the 4 initial 0's, is equivalent to the partial sums of the tetrahedral numbers A000292.  Jeremy Cahill (jcahill(AT)inbox.com), Apr 15 2009
If the first 3 zeros are disregarded, that is, if one looks at binomial(n+3, 4) with n>=0, then it becomes a 'Matryoshka doll' sequence with alpha=0: seq(add(add(add(i,i=alpha..k),k=alpha..n),n=alpha..m),m=alpha..50).  Peter Luschny, Jul 14 2009
For n>=1, a(n) is the number of ndigit numbers the binary expansion of which contains two runs of 0's.  Vladimir Shevelev, Jul 30 2010
For n>0, a(n) is the number of crossing set partitions of {1,2,..,n} into n2 blocks.  Peter Luschny, Apr 29 2011
The Kn3, Ca3 and Gi3 triangle sums of A139600 are related to the sequence given above, e.g., Gi3(n) = 2*A000332(n+3)  A000332(n+2) + 7*A000332(n+1). For the definitions of these triangle sums, see A180662.  Johannes W. Meijer, Apr 29 2011
For n > 3, a(n) is the hyperWiener index of the path graph on n2 vertices.  Emeric Deutsch, Feb 15 2012
Except for the four initial zeros, number of all possible tetrahedra of any size, having the same orientation as the original regular tetrahedron, formed when intersecting the latter by planes parallel to its sides and dividing its edges into n equal parts.  V.J. Pohjola, Aug 31 2012
a(n+3) is the number of different ways to color the faces (or the vertices) of a regular tetrahedron with n colors if we count mirror images as the same.


REFERENCES

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 828.
A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 196.
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 74, Problem 8.
L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 2, p. 7.
J. C. P. Miller, editor, Table of Binomial Coefficients. Royal Society Mathematical Tables, Vol. 3, Cambridge Univ. Press, 1954.
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).
Charles W. Trigg: Mathematical Quickies. New York: Dover Publications, Inc., 1985, p. 53, #191
A. F. Y. Zhao, Pattern Popularity in Multiply Restricted Permutations, Journal of Integer Sequences, 17 (2014), #14.10.3.


LINKS

Franklin T. AdamsWatters, Table of n, a(n) for n = 0..1002
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
Brandy Amanda Barnette, Counting Convex Sets on Products of Totally Ordered Sets, Masters Theses & Specialist Projects, Paper 1484, 2015.
P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.
Paul Erdős, Norbert Kaufman, R. H. Koch and Arthur Rosenthal, E750 (Interior diagonal points)Amer. Math. Monthly, 54 (Jun, 1947), p. 344.
Th. Gruner, A. Kerber, R. Laue and M. Meringer, Mathematics for Combinatorial Chemistry
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 254
Milan Janjic, Two Enumerative Functions
Hyun Kwang Kim, On Regular Polytope Numbers, Proc. Amer. Math. Soc., 131 (2002), 6575.
Alexsandar Petojevic, The Function vM_m(s; a; z) and Some WellKnown Sequences, Journal of Integer Sequences, Vol. 5 (2002), Article 02.1.7
Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992.
Simon Plouffe, 1031 Generating Functions and Conjectures, Université du Québec à Montréal, 1992.
Les Reid, Counting Triangles in an Array
Luis Manuel Rivera, Integer sequences and kcommuting permutations, arXiv preprint arXiv:1406.3081, 2014
Eric Weisstein's World of Mathematics, Composition
Eric Weisstein's World of Mathematics, Pentatope Number
Eric Weisstein's World of Mathematics, Pentatope
Index entries for linear recurrences with constant coefficients, signature (5,10,10,5,1).


FORMULA

a(n) = n*(n1)*(n2)*(n3)/24.
G.f.: x^4/(1x)^5.  Simon Plouffe in his 1992 dissertation
a(n) = n*a(n1)/(n4).  Benoit Cloitre, Apr 26 2003, R. J. Mathar, Jul 07 2009
a(n) = sum(k=1, n3, sum(i=1, k, i*(i+1)/2)).  Benoit Cloitre, Jun 15 2003
Convolution of natural numbers {1, 2, 3, 4, ...} and A000217, the triangular numbers {1, 3, 6, 10, ...}.  Jon Perry, Jun 25 2003
a(n+1) = [(n^5(n1)^5)(n^3(n1)^3)]/24  (n^5(n1)^51)/30; a(n) = A006322(n2)A006325(n1).  Xavier Acloque, Oct 20 2003; R. J. Mathar, Jul 07 2009
a(4n+2) = Pyr(n+4, 4n+2) where the polygonal pyramidal numbers are defined for integers A>2 and B>=0 by Pyr(A, B) = Bth Agonal pyramid number = [(A2)*B^3 + 3*B^2  (A5)*B]/6; For all positive integers i and the pentagonal number function P(x) = x*(3*x1)/2: a(3i2) = P(P(i)) and a(3i1) = P(P(i) + i); 1 + 24*a(n) = (n^2 + 3*n + 1)^2.  Jonathan Vos Post, Nov 15 2004
First differences of A000389(n).  Alexander Adamchuk, Dec 19 2004
The sum of the first n tetrahedral numbers (A000292).  Martin Steven McCormick (mathseq(AT)wazer.net), Apr 06 2005
Starting (1, 5, 15, 35,...), = binomial transform of [1, 4, 6, 4, 1, 0, 0, 0,...].  Gary W. Adamson, Dec 28 2007
Sum_{n>=4} 1/a(n) = 4/3, from the Taylor expansion of (1x)^3*log(1x) in the limit x>1.  R. J. Mathar, Jan 27 2009
A034263(n)=(n+1)*a(n+4)sum[a(i), i=0..n+3]. Also A132458(n)=a(n)^2a(n1)^2 for n>0.  Bruno Berselli, Dec 29 2010
a(0)=0, a(1)=0, a(2)=0, a(3)=0, a(4)=1, a(n) = 5*a(n1)  10*a(n2) + 10*a(n3)  5*a(n4) + a(n5).  Harvey P. Dale, Aug 22 2011
a(n) = (binomial(n1,2)^2binomial(n1,2))/6.  Gary Detlefs, Nov 20 2011
a(n) = sum_{k=1..n2} ( sum_{i=1..k} i*(nk2) ).  Wesley Ivan Hurt, Sep 25 2013
a(n) = (A000217(A000217(n  2)  1))/3 = ((((n  2)^2 + (n  2))/2)^2  (((n  2)^2 + (n  2))/2))/(2*3).  Raphie Frank, Jan 16 2014
Sum(n>=0, a(n)/n!) = e/24. Sum(n>=3, a(n)/(n3)!) = 73*e/24. See A067764 regarding the second ratio.  Richard R. Forberg, Dec 26 2013
Sum(n>=4, (1)^(n + 1)/a(n)) = 32*log(2)  64/3 = A242023 = 0.847376444589... .  Richard R. Forberg, Aug 11 2014
4/(Sum(n>=m, 1/a(n))) = A027480(m3), for m>=4.  Richard R. Forberg, Aug 12 2014
E.g.f.: x^4*exp(x)/24.  Robert Israel, Nov 23 2014
a(n+3) = C(n,1)+3C(n,2)+3C(n,3)+C(n,4). Each term indicates the number of ways to use n colors to color a tetrahedron with exactly 1, 2, 3, or 4 colors.


MAPLE

A000332 := n>binomial(n, 4); [seq(binomial(n, 4), n=0..100)];


MATHEMATICA

Table[ Binomial[n, 4], {n, 0, 45} ]
Table[(n4)(n3)(n2)(n1)/24, {n, 100}] (* Artur Jasinski, Dec 02 2007 *)
LinearRecurrence[{5, 10, 10, 5, 1}, {0, 0, 0, 0, 1}, 45] (* Harvey P. Dale, Aug 22 2011 *)
CoefficientList[Series[x^4 / (1  x)^5, {x, 0, 40}], x] (* Vincenzo Librandi, Nov 23 2014 *)


PROG

(PARI) a(n)=binomial(n, 4);
(MAGMA) [Binomial(n, 4): n in [0..50]]; // Vincenzo Librandi, Nov 23 2014


CROSSREFS

Cf. A053134, A053126, A000389, A000579A000582, A075733, A006322, A006325.
Cf. also A000583, A014820, A092181, A092182, A092183.
Cf. A000217, A000292.
Cf. A158824.
Cf. A006008 (Number of ways to color the faces (or vertices) of a regular tetrahedron with n colors when mirror images are counted as two).
Cf. A104712 (third column, k=4).
Sequence in context: A000743 A138779 A090580 * A140227 A049016 A139761
Adjacent sequences: A000329 A000330 A000331 * A000333 A000334 A000335


KEYWORD

nonn,easy,nice


AUTHOR

N. J. A. Sloane


EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Mar 14 2000
Attribute "conjectured" removed from Simon Plouffe g.f. by R. J. Mathar, Mar 11 2009
Some formulas that referred to another offset corrected by R. J. Mathar, Jul 07 2009
First Mathematica program corrected by Harvey P. Dale, Aug 22 2011
Broken link to Hyun Kwang Kim's paper fixed by Felix Fröhlich, Jun 16 2014


STATUS

approved



