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G.f.: Product_{k>=1} (1+x^k)^(2*k-1).
11

%I #13 Jun 08 2018 08:30:41

%S 1,1,3,8,15,34,67,133,255,486,901,1649,2984,5312,9373,16342,28221,

%T 48283,81928,137858,230278,381919,629156,1029933,1675856,2711288,

%U 4362575,6983196,11122327,17630798,27820283,43706461,68375137,106534093,165340844,255643289

%N G.f.: Product_{k>=1} (1+x^k)^(2*k-1).

%H Vaclav Kotesovec, <a href="/A255835/b255835.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) ~ Zeta(3)^(1/6) * exp(-Pi^4 / (2592*Zeta(3)) - Pi^2 * n^(1/3) / (12*(3*Zeta(3))^(1/3)) + 3^(4/3)/2 * Zeta(3)^(1/3) * n^(2/3)) / (2^(1/6) * 3^(1/3) * sqrt(Pi) * n^(2/3)), where Zeta(3) = A002117.

%F G.f.: exp(Sum_{k>=1} (-1)^(k+1)*x^k*(1 + x^k)/(k*(1 - x^k)^2)). - _Ilya Gutkovskiy_, Jun 07 2018

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

%Y Cf. A026007, A219555, A052812, A253289, A255834.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, Mar 07 2015