A276527 - OEIS

%I #9 Nov 16 2016 04:10:25

%S 1,-1,1,-3,5,-8,12,-21,37,-59,92,-153,256,-409,654,-1073,1754,-2824,

%T 4552,-7394,12010,-19406,31337,-50782,82306,-133072,215152,-348346,

%U 563939,-912217,1475604,-2388075,3864808,-6252750,10115987,-16369340,26488326,-42857128

%N Expansion of Product_{k>=1} 1 / (1 + x^k - x^(2*k)).

%H Vaclav Kotesovec, <a href="/A276527/b276527.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) ~ -p / (sqrt(5) * r^(n+1)), where r = -(sqrt(5)-1)/2 and p = Product_{n>1} 1/(1 + r^n - r^(2*n)) = 1.0964214808924344474065093...

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

%Y Cf. A003105, A162891.

%Y Cf. A000726, A109389, A263401.

%K sign

%O 0,4

%A _Vaclav Kotesovec_, Nov 16 2016