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%I #11 Aug 23 2019 20:51:12
%S 1,4,24,108,512,2164,9464,39004,163008,663588,2713752,10954764,
%T 44328512,178160724,716821752,2874497660,11532111232,46187508676,
%U 185028540696,740595436652,2964628293504,11862432443764,47467812675320,189902835709212,759756868215872
%N Expansion of Product_{k>=1} 1/(1 - 4*k*x^k).
%H Vaclav Kotesovec, <a href="/A265975/b265975.txt">Table of n, a(n) for n = 0..1000</a>
%F a(n) ~ c * 4^n, where c = Product_{m>=2} 1/(1 - m/4^(m-1)) = 2.700170514502619666262858845683166558216386190684736249639219328278569...
%p b:= proc(n, i) option remember; `if`(n=0 or i=1,
%p 4^n, b(n, i-1) +i*4*b(n-i, min(n-i, i)))
%p end:
%p a:= n-> b(n$2):
%p seq(a(n), n=0..32); # _Alois P. Heinz_, Aug 23 2019
%t nmax=40; CoefficientList[Series[Product[1/(1-4*k*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
%Y Cf. A006906, A265951, A265974, A265976.
%Y Cf. A246935, A246936.
%K nonn
%O 0,2
%A _Vaclav Kotesovec_, Dec 19 2015
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