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 A386595 #5 Jul 27 2025 11:29:11
%S A386595 1,4,3,4,1,12,1,4,3,4,1,19,1,8,6,4,1,12,1,4,3,4,1,19,1,4,3,8,1,24,1,4,
%T A386595 3,4,3,19,1,4,3,4,1,24,1,4,6,4,1,19,1,4,3,4,1,12,1,13,3,4,1,31,1,4,3,
%U A386595 4,1,12,1,4,3,16,1,19,1,4,6,4,1,19,1,4,3,4,1,31,1,4,3,4,1,24,1,4,3,4,1,19,1,8,3,4
%N A386595 a(n) = Sum_{d|n} sigma(d)/phi(d) * c(d), where c = A351114.
%C A386595 For each divisor d of n, add sigma(d)/phi(d) if phi(d) | sigma(d), else add 0.
%t A386595 Table[Sum[(DivisorSigma[1, d]/EulerPhi[d])*(1 - Ceiling[DivisorSigma[1, d]/EulerPhi[d]] + Floor[DivisorSigma[1, d]/EulerPhi[d]]), {d, Divisors[n]}], {n, 100}]
%Y A386595 Cf. A000010 (phi), A000203 (sigma), A020492 (balanced numbers), A351114.
%K A386595 nonn
%O A386595 1,2
%A A386595 _Wesley Ivan Hurt_, Jul 26 2025