A303443 - OEIS

A303443

Expansion of Product_{k>=1} ((1 + 8^k*x^k)/(1 - 8^k*x^k))^(1/8^k).

%I #11 Apr 25 2018 07:17:26

%S 1,2,4,50,98,1830,7264,89326,247252,4520886,20225372,241414342,

%T 786393322,12744704970,62688642800,771140700226,2635449405522,

%U 40907909552038,211134761381948,2451388697035478,9148627707018230,143396849321918482,743716982801639120

%N Expansion of Product_{k>=1} ((1 + 8^k*x^k)/(1 - 8^k*x^k))^(1/8^k).

%H Seiichi Manyama, <a href="/A303443/b303443.txt">Table of n, a(n) for n = 0..1000</a>

%t nmax = 30; CoefficientList[Series[Exp[Sum[((-1)^j - 1) / (j*(1 - 1/(8^(j-1)*x^j))), {j, 1, nmax}]], {x, 0, nmax}], x] (* _Vaclav Kotesovec_, Apr 25 2018 *)

%o (PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, ((1+8^k*x^k)/(1-8^k*x^k))^(1/8^k)))

%Y Cf. A303381, A303438, A303442.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Apr 24 2018