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 A342432 #22 May 23 2021 07:28:00
%S A342432 1,2,5,22,129,1411,16813,266372,4787349,100391653,2357947701,
%T A342432 61980047702,1792160394049,56707753687079,1946197516142925,
%U A342432 72061992621375496,2862423051509815809,121441389759089405193,5480386857784802185957
%N A342432 a(n) = Sum_{k=1..n} gcd(k,n)^(n-2).
%H A342432 Seiichi Manyama, <a href="/A342432/b342432.txt">Table of n, a(n) for n = 1..388</a>
%F A342432 a(n) = Sum_{d|n} phi(n/d) * d^(n-2).
%F A342432 a(n) = Sum_{d|n} mu(n/d) * d * sigma_(n-3)(d).
%F A342432 a(n) ~ n^(n-2). - _Vaclav Kotesovec_, May 23 2021
%t A342432 a[n_] := Sum[GCD[k, n]^(n - 2), {k, 1, n}]; Array[a, 20] (* _Amiram Eldar_, Mar 12 2021 *)
%o A342432 (PARI) a(n) = sum(k=1, n, gcd(k, n)^(n-2));
%o A342432 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*d^(n-2));
%o A342432 (PARI) a(n) = sumdiv(n, d, moebius(n/d)*d*sigma(d, n-3));
%Y A342432 Cf. A000010, A332517, A342412, A342433, A343510.
%K A342432 nonn
%O A342432 1,2
%A A342432 _Seiichi Manyama_, Mar 12 2021