cp's OEIS Frontend

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.

A342675 a(n) = Sum_{d|n} d^(n-d+1).

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%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