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 A363649 #13 Jul 19 2023 02:19:26
%S A363649 0,1,2,4,4,14,6,56,62,266,10,3991,12,6158,84996,225296,16,2881607,18,
%T A363649 96995583,87740548,2621462,22,30762215703,122070312524,50331674,
%U A363649 84457666628,8631957089039,28,885639790229244,30,2814753793638432,76826598191124
%N A363649 Expansion of Sum_{k>0} x^(2*k)/(1 - (k*x)^k)^2.
%F A363649 a(n) = Sum_{d|n} (n/d)^(n-2*n/d) * (d-1).
%F A363649 If p is prime, a(p) = p - 1.
%t A363649 a[n_] := DivisorSum[n, (n/#)^(n-2*n/#) * (#-1) &]; Array[a, 33] (* _Amiram Eldar_, Jul 18 2023 *)
%o A363649 (PARI) a(n) = sumdiv(n, d, (n/d)^(n-2*n/d)*(d-1));
%Y A363649 Cf. A359112, A363646.
%Y A363649 Cf. A363641.
%K A363649 nonn
%O A363649 1,3
%A A363649 _Seiichi Manyama_, Jun 13 2023