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A265975
Expansion of Product_{k>=1} 1/(1 - 4*k*x^k).
4
1, 4, 24, 108, 512, 2164, 9464, 39004, 163008, 663588, 2713752, 10954764, 44328512, 178160724, 716821752, 2874497660, 11532111232, 46187508676, 185028540696, 740595436652, 2964628293504, 11862432443764, 47467812675320, 189902835709212, 759756868215872
OFFSET
0,2
LINKS
FORMULA
a(n) ~ c * 4^n, where c = Product_{m>=2} 1/(1 - m/4^(m-1)) = 2.700170514502619666262858845683166558216386190684736249639219328278569...
MAPLE
b:= proc(n, i) option remember; `if`(n=0 or i=1,
4^n, b(n, i-1) +i*4*b(n-i, min(n-i, i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..32); # Alois P. Heinz, Aug 23 2019
MATHEMATICA
nmax=40; CoefficientList[Series[Product[1/(1-4*k*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Dec 19 2015
STATUS
approved