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%I #28 Jul 25 2023 17:31:25
%S 0,1,4,11,20,40,56,95,124,186,220,336,364,512,584,775,816,1129,1140,
%T 1526,1600,1992,2024,2720,2620,3290,3400,4176,4060,5280,4960,6231,
%U 6208,7362,7216,9195,8436,10280,10248,12270,11480,14432,13244,16192,15884,18240
%N Expansion of Sum_{k>0} x^(2*k)/(1-x^k)^4.
%H Seiichi Manyama, <a href="/A363604/b363604.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = (sigma_3(n) - sigma(n))/6 = A092348(n)/6.
%F G.f.: Sum_{k>0} binomial(k+1,3) * x^k/(1 - x^k).
%t a[n_] := (DivisorSigma[3, n] - DivisorSigma[1, n])/6; Array[a, 50] (* _Amiram Eldar_, Jul 25 2023 *)
%o (PARI) my(N=50, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(2*k)/(1-x^k)^4)))
%Y Cf. A000292, A032741, A065608, A069153, A363605, A363606.
%Y Cf. A059358, A363607, A363611.
%Y Cf. A000203, A001158, A092348.
%K nonn,easy
%O 1,3
%A _Seiichi Manyama_, Jun 11 2023
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