This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A363645 #11 Jul 19 2023 02:19:24 %S A363645 1,5,11,29,36,109,85,297,256,801,287,2881,456,5965,3766,17489,970, %T A363645 57385,1331,125681,63498,294933,2301,1072865,24801,1867009,1087030, %U A363645 4942561,4496,15697761,5457,28721057,16895770,63511593,1404306,225177013,9140,348661477 %N A363645 Expansion of Sum_{k>0} x^k/(1 - k*x^k)^4. %F A363645 a(n) = Sum_{d|n} (n/d)^(d-1) * binomial(d+2,3). %t A363645 a[n_] := DivisorSum[n, (n/#)^(# - 1)*Binomial[# + 2, 3] &]; Array[a, 40] (* _Amiram Eldar_, Jul 18 2023 *) %o A363645 (PARI) a(n) = sumdiv(n, d, (n/d)^(d-1)*binomial(d+2, 3)); %Y A363645 Cf. A167531, A363642. %Y A363645 Cf. A059358. %K A363645 nonn %O A363645 1,2 %A A363645 _Seiichi Manyama_, Jun 13 2023