A023702 -id:A023702 - cp's OEIS frontend

A043332 Duplicate of A023702.

80, 161, 188, 215, 224, 233, 236, 239, 240, 241, 323, 404, 431, 458, 467

Offset: 1

dead

A117592 a(n) = a(3n) = a(3n+1) = a(3n+2)/2 with a(0)=1.

1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4

Offset: 0

Paul Barry, Apr 05 2006

Row sums of number triangle A117944.
Product of the nonzero digits of (n written in base 3). - Ilya Gutkovskiy, Nov 15 2020
a(n) = 1, 2, 4, 8, 16, 32, 64 iff n is respectively in A005836, A023699, A023700, A023701, A023702, A023703, A023704. - Bernard Schott, Dec 04 2020

Felix Fröhlich, Table of n, a(n) for n = 0..10000 (first 2001 terms from Vincenzo Librandi)

See A338882 for similar sequences.
Cf. A081603 (log_2), A117942 (signed), A117944.
Cf. A005836, A023699, A023700, A023701, A023702, A023703, A023704.

Nest[ Join[#, #, 2#] &, {1}, 5] (* Robert G. Wilson v, Jul 27 2014 *)

a(n) = 1 << hammingweight(digits(n,3)>>1); \\ Kevin Ryde, Nov 15 2020

from gmpy2 import digits
def A117592(n): return 1<Chai Wah Wu, Dec 05 2024

a(n) = a(3n)/a(0) = a(3n+1)/a(1) = a(3n+2)/a(2).
a(n) = abs(A117942(n)).
G.f. A(x) satisfies: A(x) = (1 + x + 2*x^2) * A(x^3). - Ilya Gutkovskiy, Nov 15 2020
a(n) = 2^A081603(n). - Kevin Ryde, Nov 15 2020

a(0) = 1 added to the Name by Bernard Schott, Dec 04 2020

A009805 Expansion of e.g.f. tanh(sinh(x)*sin(x))/2 in odd powers of x^2.

Original entry on oeis.org

1, -124, 262096, -2681078464, 83993259325696, -6291889632188161024, 963296773204704677810176, -270352239123704851078462357504, 128399592149905444543967414059073536, -97061880731293117665388947647693059784704, 111259126741155511631646423576320132328299954176

Offset: 0

R. H. Hardin

sign

			x^2/2! - 124*x^6/6! + 262096*x^10/10! - 2681078464*x^14/14! ...

Andrew Howroyd, Table of n, a(n) for n = 0..100

Cf. A023702.

Tanh[ Sinh[ x ]*Sin[ x ] ]/2 (* [ x^(4n+2) ] *)
With[{nn=34},Take[CoefficientList[Series[Tanh[Sinh[x]Sin[x]]/2,{x,0,nn}],x] Range[0,nn]!,{3,-1,4}]] (* Harvey P. Dale, May 28 2019 *)

seq(n)={my(A=O(x^(4*n+2))); Vec(substpol(serlaplace( tanh(sinh(x + A)*sin(x + A))/2 )/x^2, x^4, x))} \\ Andrew Howroyd, Jan 12 2025

Extended with signs by Olivier Gérard, Mar 15 1997

a(9) onwards from Andrew Howroyd, Jan 12 2025

cp's OEIS Frontend

A043332 Duplicate of A023702.

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A117592 a(n) = a(3n) = a(3n+1) = a(3n+2)/2 with a(0)=1.

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A009805 Expansion of e.g.f. tanh(sinh(x)*sin(x))/2 in odd powers of x^2.

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