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%I #28 Sep 08 2022 08:44:46
%S 1,4,14,48,137,380,998,2488,5996,14020,31868,70616,153389,326248,
%T 681914,1402880,2841769,5678316,11201956,21833480,42081245,80264752,
%U 151572328,283577152,525894397,967100700,1764378830,3194682272,5742739237,10252117308,18182247316
%N Expansion of Product_{m>=1} (1 + m*q^m)^4.
%C This sequence is obtained from the generalized Euler transform in A266964 by taking f(n) = -4, g(n) = -n. - _Seiichi Manyama_, Dec 29 2017
%H Seiichi Manyama, <a href="/A022632/b022632.txt">Table of n, a(n) for n = 0..1000</a>
%F G.f.: exp(4*Sum_{j>=1} Sum_{k>=1} (-1)^(j+1)*k^j*x^(j*k)/j). - _Ilya Gutkovskiy_, Feb 08 2018
%t CoefficientList[Take[Expand[Product[(1 + k x^k)^4, {k, 40}]], 40], x] (* _Vincenzo Librandi_, Jan 24 2018 *)
%o (Magma) Coefficients(&*[(1+m*x^m)^4:m in [1..40]])[1..40] where x is PolynomialRing(Integers()).1; // _Vincenzo Librandi_, Jan 24 2018
%o (PARI) m=50; q='q+O('q^m); Vec(prod(n=1,m,(1+n*q^n)^4)) \\ _G. C. Greubel_, Feb 16 2018
%Y Column k=4 of A297321.
%K nonn
%O 0,2
%A _N. J. A. Sloane_
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