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 A342396 #11 Mar 10 2021 12:28:56
%S A342396 1,2,6,31,355,3150,67172,904085,22998481,427799450,14914341926,
%T A342396 287337926355,13421957361111,339940911160914,15434209582905140,
%U A342396 493467700905592777,28101527071305611529,836396358233559195382
%N A342396 a(n) = Sum_{k=1..n} k^(n/gcd(k,n) - 1).
%F A342396 If p is prime, a(p) = A031971(p-1) + 1.
%t A342396 a[n_] := Sum[k^(n/GCD[k, n] - 1), {k, 1, n}]; Array[a, 18] (* _Amiram Eldar_, Mar 10 2021 *)
%o A342396 (PARI) a(n) = sum(k=1, n, k^(n/gcd(k, n)-1));
%Y A342396 Cf. A031971, A332621, A342394, A342395.
%K A342396 nonn,easy
%O A342396 1,2
%A A342396 _Seiichi Manyama_, Mar 10 2021