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 A342675 #16 Mar 22 2021 14:59:45 %S A342675 1,3,4,13,6,120,8,1161,2197,16148,12,603190,14,5773008,50422464, %T A342675 201359377,18,16590656229,20,269768284118,4748723771432,3138430473896, %U A342675 24,2972582195034162,476837158203151,3937376419253748,1350852564961601560,4066515044181860654,30,1036488835382356683530,32 %N A342675 a(n) = Sum_{d|n} d^(n-d+1). %H A342675 Seiichi Manyama, <a href="/A342675/b342675.txt">Table of n, a(n) for n = 1..599</a> %F A342675 G.f.: Sum_{k>=1} k * x^k/(1 - (k * x)^k). %F A342675 If p is prime, a(p) = 1 + p. %t A342675 a[n_] := DivisorSum[n, #^(n - # + 1) &]; Array[a, 30] (* _Amiram Eldar_, Mar 18 2021 *) %o A342675 (PARI) a(n) = sumdiv(n, d, d^(n-d+1)); %o A342675 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=1, N, k*x^k/(1-(k*x)^k))) %Y A342675 Cf. A023887, A294645, A342628, A342677. %K A342675 nonn %O A342675 1,2 %A A342675 _Seiichi Manyama_, Mar 18 2021