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 A342540 #16 Mar 20 2021 11:35:50
%S A342540 1,2,6,11,260,68,46662,16518,1680134,524296,10000000010,4204550,
%T A342540 8916100448268,26121388044,4398583447560,35185445896204,
%U A342540 18446744073709551632,33853319413772,39346408075296537575442,144116012711673868,3833767304764361539596,2000000000000000000020
%N A342540 a(n) = Sum_{k=1..n} phi(gcd(k, n))^(n-1).
%H A342540 Seiichi Manyama, <a href="/A342540/b342540.txt">Table of n, a(n) for n = 1..388</a>
%F A342540 a(n) = Sum_{d|n} phi(n/d) * phi(d)^(n-1).
%F A342540 If p is prime, a(p) = p-1 + (p-1)^(p-1).
%t A342540 a[n_] := DivisorSum[n, EulerPhi[n/#] * EulerPhi[#]^(n - 1) &]; Array[a, 20] (* _Amiram Eldar_, Mar 15 2021 *)
%o A342540 (PARI) a(n) = sum(k=1, n, eulerphi(gcd(k, n))^(n-1));
%o A342540 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*eulerphi(d)^(n-1));
%Y A342540 Cf. A000010, A029935, A342471, A342539, A342542, A342544.
%K A342540 nonn
%O A342540 1,2
%A A342540 _Seiichi Manyama_, Mar 15 2021