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 A342613 #19 Mar 18 2021 08:24:54
%S A342613 1,2,17,34,4097,386,1679617,263170,60470273,20971522,1000000000001,
%T A342613 67223554,1283918464548865,3291294892034,281543697235969,
%U A342613 2251868534210562,4722366482869645213697,4265518198947842,12748236216396078174437377,9223671104051085314,552066177293775007645697,1100000000000000000000002
%N A342613 a(n) = Sum_{d|n} phi(n/d)^(n+d).
%H A342613 Seiichi Manyama, <a href="/A342613/b342613.txt">Table of n, a(n) for n = 1..388</a>
%F A342613 a(n) = Sum_{k=1..n} phi(n/gcd(k,n))^(n + gcd(k,n) - 1).
%F A342613 G.f.: Sum_{k>=1} phi(k)^(k+1) * x^k/(1 - phi(k)^(k+1) * x^k).
%F A342613 If p is prime, a(p) = 1 + (p-1)^(p+1).
%t A342613 a[n_] := DivisorSum[n, EulerPhi[n/#]^(n + #) &]; Array[a, 20] (* _Amiram Eldar_, Mar 17 2021 *)
%o A342613 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)^(n+d));
%o A342613 (PARI) a(n) = sum(k=1, n, eulerphi(n/gcd(k, n))^(n+gcd(k, n)-1));
%o A342613 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=1, N, eulerphi(k)^(k+1)*x^k/(1-eulerphi(k)^(k+1)*x^k)))
%Y A342613 Cf. A342608, A342612, A342620.
%K A342613 nonn
%O A342613 1,2
%A A342613 _Seiichi Manyama_, Mar 16 2021