%I #15 Apr 14 2019 11:55:02
%S 1,-2,-6,-4,22,72,92,-48,-522,-1294,-1624,300,6948,19032,30192,20432,
%T -45578,-202788,-437178,-599460,-311112,1038624,4023532,8423280,
%U 11892004,8429270,-12073032,-60747944,-139842736,-223644552,-232762256,-15050944,636838518
%N Expansion of Product_{n>0} ((1-x^n)/(1+x^n))^(n^2) in powers of x.
%H Seiichi Manyama, <a href="/A285988/b285988.txt">Table of n, a(n) for n = 0..10000</a>
%F a(0) = 1, a(n) = -(2/n)*Sum_{k=1..n} A007331(k)*a(n-k) for n > 0.
%F G.f.: exp(Sum_{k>=1} (sigma_3(k) - sigma_3(2*k))*x^k/(4*k)). - _Ilya Gutkovskiy_, Apr 14 2019
%Y Product_{n>0} ((1-x^n)/(1+x^n))^(n^m): A002448 (m=0), A285675 (m=1), this sequence (m=2), A285990 (m=3), A285991 (m=4).
%Y Cf. A007331, A206622.
%K sign
%O 0,2
%A _Seiichi Manyama_, Apr 30 2017