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Expansion of Product_{k>=1} 1/(1 - k*x^(k^2)).
5

%I #11 Apr 15 2017 15:23:45

%S 1,1,1,1,3,3,3,3,7,10,10,10,18,24,24,24,44,56,65,65,105,129,147,147,

%T 227,292,328,355,515,645,717,771,1107,1367,1562,1670,2429,2949,3339,

%U 3555,5073,6181,6961,7546,10582,13059,14619,15789,21925,26886,30235,32575

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

%H Vaclav Kotesovec, <a href="/A285245/b285245.txt">Table of n, a(n) for n = 0..10000</a>

%F a(n) ~ c * 2^(n/4), where

%F c = 6.362854320457366874306510139107365081972383711876544726... if mod(n,4)=0

%F c = 6.470997903106304472752360748461108347899808941622559468... if mod(n,4)=1

%F c = 6.154059402265470959096395812318265046714869376472639022... if mod(n,4)=2

%F c = 5.624747659153211728892605407048217108787120474872434485... if mod(n,4)=3

%t nmax = 100; CoefficientList[Series[Product[1/(1 - k*x^(k^2)), {k,1,nmax}], {x,0,nmax}], x]

%Y Cf. A001156, A006906, A285243, A285244.

%K nonn

%O 0,5

%A _Vaclav Kotesovec_, Apr 15 2017