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 A245786 #11 Sep 08 2022 08:46:09 %S A245786 1,672,4680,30240,23569920,45532800,275890944,14182439040, %T A245786 153003540480,403031236608,518666803200 %N A245786 Numbers n such that k(n) = (n/tau(n) + sigma(n)/n) is an integer. %C A245786 Numbers n such that A245784(n) / A245785(n) = (n / A000005(n) + A000203(n) / n) is an integer. %C A245786 Sequence of numbers k(n): 2, 31, 101, 319, 73660, 118579, … %C A245786 Conjecture: Subsequence of A216793. %C A245786 Refactorable multiply-perfect numbers (A245782) are members of this sequence. %C A245786 a(12) > 10^13. - _Giovanni Resta_, Jul 13 2015 %F A245786 A245785(a(n)) = 1. %e A245786 672 is in sequence because 672/tau(672) + sigma(672)/672 = 672/24 + 2016/672 = 31 (integer). %o A245786 (Magma) [n: n in [1..100000] | (Denominator((n/(#[d: d in Divisors(n)])) + (SumOfDivisors(n)/n)) eq 1)] %o A245786 (PARI) for(n=1, 10^8, s=n/numdiv(n); t=sigma(n)/n; if(floor(s+t)==s+t, print1(n, ", "))) \\ _Derek Orr_, Aug 15 2014 %Y A245786 Cf. A000005, A000203, A245784, A245785, A245782. %K A245786 nonn %O A245786 1,2 %A A245786 _Jaroslav Krizek_, Aug 15 2014 %E A245786 a(7)-a(11) from _Giovanni Resta_, Jul 13 2015