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 A363631 #17 Jul 19 2023 02:20:02
%S A363631 -4,6,-24,41,-60,70,-124,206,-244,236,-368,560,-564,566,-896,1175,
%T A363631 -1144,1180,-1544,2042,-2168,1942,-2604,3650,-3336,3100,-4304,5096,
%U A363631 -4964,4940,-5988,7720,-7528,6636,-8616,10809,-9884,9126,-12064,14548,-13248,12796,-15184,18192,-18412,15830
%N A363631 Expansion of Sum_{k>0} (1/(1+x^k)^4 - 1).
%H A363631 Seiichi Manyama, <a href="/A363631/b363631.txt">Table of n, a(n) for n = 1..10000</a>
%F A363631 G.f.: Sum_{k>0} binomial(k+3,3) * (-x)^k/(1 - x^k).
%F A363631 a(n) = Sum_{d|n} (-1)^d * binomial(d+3,3).
%t A363631 a[n_] := DivisorSum[n, (-1)^#*Binomial[# + 3, 3] &]; Array[a, 50] (* _Amiram Eldar_, Jul 18 2023 *)
%o A363631 (PARI) a(n) = sumdiv(n, d, (-1)^d*binomial(d+3, 3));
%Y A363631 Cf. A363629, A363630.
%Y A363631 Cf. A320901, A363598, A363616, A363617.
%K A363631 sign,easy
%O A363631 1,1
%A A363631 _Seiichi Manyama_, Jun 12 2023