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 A363646 #14 Jul 17 2023 00:59:24
%S A363646 2,11,58,565,6256,95762,1647094,33752329,774919720,20029303030,
%T A363646 570623341234,17838801038274,605750213184520,22226048320465666,
%U A363646 875787902918124708,36894332593824661521,1654480523772673528372,78693266840741507386757
%N A363646 Expansion of Sum_{k>0} (1/(1 - (k*x)^k)^2 - 1).
%F A363646 a(n) = Sum_{d|n} (n/d)^n * (d+1).
%t A363646 a[n_] := DivisorSum[n, (n/#)^n * (# + 1) &]; Array[a, 20] (* _Amiram Eldar_, Jul 17 2023 *)
%o A363646 (PARI) a(n) = sumdiv(n, d, (n/d)^n*(d+1));
%Y A363646 Cf. A023887, A338663, A363647, A363648.
%Y A363646 Cf. A007503, A362683.
%K A363646 nonn
%O A363646 1,1
%A A363646 _Seiichi Manyama_, Jun 13 2023