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 A369687 #9 Jul 16 2025 20:27:02
%S A369687 0,2,3,2,5,7,7,4,9,21,11,13,13,71,106,16,17,73,19,41,778,1035,23,97,
%T A369687 625,4109,729,113,29,362,31,256,59170,65553,18026,145,37,262163,
%U A369687 531610,881,41,4874,43,1145,22186,4194327,47,6817,117649,1049201,43047010,4265,53,262873,9780266,6497
%N A369687 a(n) = Sum_{p|n, p prime} p^phi(n/p).
%F A369687 a(p^k) = p^((p-1)*p^(k-2)+floor(1/k)/p) for p prime and k>=1. - _Wesley Ivan Hurt_, Jul 16 2025
%t A369687 Table[DivisorSum[n, #^EulerPhi[n/#] &, PrimeQ[#] &], {n, 60}]
%o A369687 (Python)
%o A369687 from sympy import totient, primefactors
%o A369687 def A369687(n): return sum(p**totient(n//p) for p in primefactors(n)) # _Chai Wah Wu_, Jan 28 2024
%Y A369687 Cf. A000010 (phi), A347104, A369779, A369782.
%K A369687 nonn,easy
%O A369687 1,2
%A A369687 _Wesley Ivan Hurt_, Jan 28 2024