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 A321386 #13 Nov 10 2018 09:14:13
%S A321386 1,1,10,61,626,7768,117650,2097085,43046731,999999376,25937424602,
%T A321386 743008362964,23298085122482,793714773136496,29192926025391260,
%U A321386 1152921504604749757,48661191875666868482,2185911559738653493015,104127350297911241532842,5242879999999998999999436,278218429446951548637314060
%N A321386 a(n) = Sum_{d|n} (-1)^(n/d+1)*d^(d-1).
%F A321386 G.f.: Sum_{k>=1} k^(k-1)*x^k/(1 + x^k).
%F A321386 a(n) ~ n^(n-1). - _Vaclav Kotesovec_, Nov 09 2018
%t A321386 Table[Sum[(-1)^(n/d + 1) d^(d - 1), {d, Divisors[n]}], {n, 21}]
%t A321386 nmax = 21; Rest[CoefficientList[Series[Sum[k^(k - 1) x^k/(1 + x^k), {k, 1, nmax}], {x, 0, nmax}], x]]
%o A321386 (PARI) a(n) = sumdiv(n, d, (-1)^(n/d+1)*d^(d-1)); \\ _Michel Marcus_, Nov 09 2018
%Y A321386 Cf. A000169, A262843, A321388.
%K A321386 nonn
%O A321386 1,3
%A A321386 _Ilya Gutkovskiy_, Nov 08 2018