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 A342437 #21 Mar 13 2021 10:05:07
%S A342437 1,2,3,5,5,14,7,25,25,74,11,161,13,398,383,657,17,2110,19,3341,4485,
%T A342437 10262,23,19569,2521,49178,39547,74441,29,221462,31,328737,590753,
%U A342437 1048610,103379,1905565,37,4718630,6377655,5573801,41,22462826,43,31459985,40634221,92274734,47
%N A342437 a(n) = Sum_{k=1..n} gcd(k,n)^(n/gcd(k,n) - 1).
%H A342437 Seiichi Manyama, <a href="/A342437/b342437.txt">Table of n, a(n) for n = 1..5000</a>
%F A342437 a(n) = Sum_{d|n} phi(n/d) * d^(n/d-1).
%F A342437 If p is prime, a(p) = p.
%t A342437 a[n_] := Sum[GCD[k, n]^(n/GCD[k, n] - 1), {k, 1, n}]; Array[a, 50] (* _Amiram Eldar_, Mar 12 2021 *)
%o A342437 (PARI) a(n) = sum(k=1, n, gcd(k, n)^(n/gcd(k, n)-1));
%o A342437 (PARI) a(n) = sumdiv(n, d, eulerphi(n/d)*d^(n/d-1));
%Y A342437 Cf. A000010, A226459, A342421, A342424.
%K A342437 nonn
%O A342437 1,2
%A A342437 _Seiichi Manyama_, Mar 12 2021