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 A342612 #19 Mar 18 2021 08:24:47
%S A342612 1,2,5,10,257,50,46657,16450,1679681,327682,10000000001,4196098,
%T A342612 8916100448257,15237476354,4398063289345,35184640528386,
%U A342612 18446744073709551617,19747769389058,39346408075296537575425
%N A342612 a(n) = Sum_{d|n} phi(n/d)^(n-d).
%H A342612 Seiichi Manyama, <a href="/A342612/b342612.txt">Table of n, a(n) for n = 1..388</a>
%F A342612 a(n) = Sum_{k=1..n} phi(n/gcd(k,n))^(n - gcd(k,n) - 1).
%F A342612 G.f.: Sum_{k>=1} phi(k)^(k-1) * x^k/(1 - phi(k)^(k-1) * x^k).
%F A342612 If p is prime, a(p) = 1 + (p-1)^(p-1).
%t A342612 a[n_] := DivisorSum[n, EulerPhi[n/#]^(n - #) &]; Array[a, 20] (* _Amiram Eldar_, Mar 17 2021 *)
%o A342612 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)^(n-d));
%o A342612 (PARI) a(n) = sum(k=1, n, eulerphi(n/gcd(k, n))^(n-gcd(k, n)-1));
%o A342612 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=1, N, eulerphi(k)^(k-1)*x^k/(1-eulerphi(k)^(k-1)*x^k)))
%Y A342612 Cf. A000010, A342489, A342619, A342629.
%K A342612 nonn
%O A342612 1,2
%A A342612 _Seiichi Manyama_, Mar 16 2021