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 A342539 #22 May 13 2021 01:39:30
%S A342539 1,2,10,19,1028,132,279942,65798,10078726,2097160,100000000010,
%T A342539 16797702,106993205379084,156728328204,35186519703560,281479271809036,
%U A342539 295147905179352825872,203119914385420,708235345355337676357650,1152924803145924620,46005163783270994804748,20000000000000000000020
%N A342539 a(n) = Sum_{k=1..n} phi(gcd(k, n))^n.
%H A342539 Seiichi Manyama, <a href="/A342539/b342539.txt">Table of n, a(n) for n = 1..388</a>
%F A342539 a(n) = Sum_{d|n} phi(n/d) * phi(d)^n.
%F A342539 If p is prime, a(p) = p-1 + (p-1)^p.
%F A342539 a(n) = Sum_{k=1..n} phi(n/gcd(n,k))^(n-1)*phi(gcd(n,k)). - _Richard L. Ollerton_, May 09 2021
%t A342539 a[n_] := DivisorSum[n, EulerPhi[n/#] * EulerPhi[#]^n &]; Array[a, 20] (* _Amiram Eldar_, Mar 15 2021 *)
%o A342539 (PARI) a(n) = sum(k=1, n, eulerphi(gcd(k, n))^n);
%o A342539 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*eulerphi(d)^n);
%Y A342539 Cf. A000010, A029935, A332517, A342487, A342534, A342535, A342540, A342541, A342543.
%K A342539 nonn
%O A342539 1,2
%A A342539 _Seiichi Manyama_, Mar 15 2021