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A276526 Expansion of Product_{k>=1} 1/(1 - x^(2*k) + x^(3*k)). 2
1, 0, 1, -1, 2, -2, 3, -4, 7, -8, 11, -15, 22, -27, 37, -51, 70, -90, 121, -162, 220, -288, 381, -512, 688, -902, 1197, -1598, 2127, -2809, 3722, -4949, 6581, -8699, 11519, -15301, 20305, -26862, 35581, -47208, 62591, -82859, 109756, -145506, 192856, -255388 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..1000

FORMULA

a(n) ~ c * p / r^n, where r = -A075778 = -0.7548776662466927600495... is the real root of the equation r^3 - r^2 + 1 = 0, p = Product_{n>1} 1/(1 - r^(2*n) + r^(3*n)) = 1.9844809074648434... and c = 0.41149558866264576338190038... is the real root of the equation -1 + 8*c - 23*c^2 + 23*c^3 = 0.

MATHEMATICA

nmax = 50; CoefficientList[Series[1/Product[1-x^(2*k)+x^(3*k), {k, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A264905, A266686, A275820, A275821, A276519.

Sequence in context: A014692 A058670 A215367 * A091605 A145468 A125554

Adjacent sequences:  A276523 A276524 A276525 * A276527 A276528 A276529

KEYWORD

sign

AUTHOR

Vaclav Kotesovec, Nov 16 2016

STATUS

approved

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Last modified July 22 14:46 EDT 2019. Contains 325224 sequences. (Running on oeis4.)