

A161415


First differences of A160414.


8



1, 8, 12, 28, 12, 36, 36, 92, 12, 36, 36, 108, 36, 108, 108, 292, 12, 36, 36, 108, 36, 108, 108, 324, 36, 108, 108, 324, 108, 324, 324, 908, 12, 36, 36, 108, 36, 108, 108, 324, 36, 108, 108, 324, 108, 324, 324, 972, 36, 108, 108, 324, 108, 324, 324, 972, 108, 324, 324
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..59.
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 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
Omar E. Pol, Illustration of initial terms [From Omar E. Pol, Nov 11 2009]
D. Applegate, Omar E. Pol, N. J. A. Sloane, The toothpick sequence and other sequences from cellular automata, arXiv:1004.3036 [math.CO] [From R. J. Mathar, Oct 16 2010]


FORMULA

For n > 1, a(n) = 4*A048883(n1), except a(n) = 4*A048883(n1)  2n if n is a power of 2.  N. J. A. Sloane, Jul 13 2009


MAPLE

Contribution from R. J. Mathar, Oct 16 2010: (Start)
isA000079 := proc(n) if type(n, 'even') then nops(numtheory[factorset](n)) = 1 ; else false ; fi ; end proc:
A048883 := proc(n) 3^wt(n) ; end proc:
A161415 := proc(n) if n = 1 then 1; elif isA000079(n) then 4*A048883(n1)2*n ; else 4*A048883(n1) ; end if; end proc: seq(A161415(n), n=1..90) ; (End)


MATHEMATICA

a[1] = 1; a[n_] := 4*3^DigitCount[n1, 2, 1]  If[IntegerQ[Log[2, n]], 2n, 0];
Array[a, 60] (* JeanFrançois Alcover, Nov 17 2017, after N. J. A. Sloane *)


CROSSREFS

Cf. A139250, A139251, A160411, A160413, A160414, A160417.
Cf. A160727.
Cf. A048883, A161411, A162349. [From Omar E. Pol, Nov 11 2009]
Sequence in context: A072327 A218558 A181735 * A256531 A117802 A083485
Adjacent sequences: A161412 A161413 A161414 * A161416 A161417 A161418


KEYWORD

nonn


AUTHOR

Omar E. Pol, May 20 2009, Jun 13 2009


EXTENSIONS

More terms from R. J. Mathar, Oct 16 2010


STATUS

approved



