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 A360824 #16 Jul 31 2023 02:25:14 %S A360824 1,6,30,284,3130,47082,823550,16782664,387422928,10000094720, %T A360824 285311670622,8916102486528,302875106592266,11112006871683606, %U A360824 437893890382576560,18446744074918103056,827240261886336764194,39346408075331452862196 %N A360824 Expansion of Sum_{k>0} (k * x)^k / (1 - k * x^k)^(k+1). %F A360824 a(n) = Sum_{d|n} d^(d+n/d-1) * binomial(d+n/d-1,d). %F A360824 If p is prime, a(p) = p + p^p. %t A360824 a[n_] := DivisorSum[n, #^(# + n/# - 1) * Binomial[# + n/# - 1, #] &]; Array[a, 20] (* _Amiram Eldar_, Jul 31 2023 *) %o A360824 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=1, N, (k*x)^k/(1-k*x^k)^(k+1))) %o A360824 (PARI) a(n) = sumdiv(n, d, d^(d+n/d-1)*binomial(d+n/d-1, d)); %Y A360824 Cf. A339712, A343574, A360823. %K A360824 nonn %O A360824 1,2 %A A360824 _Seiichi Manyama_, Feb 22 2023