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%I #11 Jul 19 2023 02:19:24
%S 1,5,11,29,36,109,85,297,256,801,287,2881,456,5965,3766,17489,970,
%T 57385,1331,125681,63498,294933,2301,1072865,24801,1867009,1087030,
%U 4942561,4496,15697761,5457,28721057,16895770,63511593,1404306,225177013,9140,348661477
%N Expansion of Sum_{k>0} x^k/(1 - k*x^k)^4.
%F a(n) = Sum_{d|n} (n/d)^(d-1) * binomial(d+2,3).
%t a[n_] := DivisorSum[n, (n/#)^(# - 1)*Binomial[# + 2, 3] &]; Array[a, 40] (* _Amiram Eldar_, Jul 18 2023 *)
%o (PARI) a(n) = sumdiv(n, d, (n/d)^(d-1)*binomial(d+2, 3));
%Y Cf. A167531, A363642.
%Y Cf. A059358.
%K nonn
%O 1,2
%A _Seiichi Manyama_, Jun 13 2023
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