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 A343574 #12 Apr 20 2021 22:36:45 %S A343574 1,6,30,272,3130,46794,823550,16778544,387420768,10000018820, %T A343574 285311670622,8916100779324,302875106592266,11112006832146486, %U A343574 437893890380925960,18446744073860555680,827240261886336764194,39346408075300413088392 %N A343574 a(n) = Sum_{d|n} d^d * binomial(d+n/d-1, d). %F A343574 G.f.: Sum_{k >= 1} (k * x)^k/(1 - x^k)^(k+1). %F A343574 If p is prime, a(p) = p + p^p. %t A343574 a[n_] := DivisorSum[n, #^#*Binomial[# + n/# - 1, #] &]; Array[a, 20] (* _Amiram Eldar_, Apr 20 2021 *) %o A343574 (PARI) a(n) = sumdiv(n, d, d^d*binomial(d+n/d-1, d)); %o A343574 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=1, N, (k*x)^k/(1-x^k)^(k+1))) %Y A343574 Cf. A081543, A343568, A343573. %K A343574 nonn %O A343574 1,2 %A A343574 _Seiichi Manyama_, Apr 20 2021