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 A244669 #9 Sep 08 2022 08:46:08 %S A244669 1,3,4,7,6,1,8,15,13,9,12,7,14,6,8,31,18,13,20,21,32,9,24,5,31,21,40, %T A244669 1,30,1,32,63,16,27,48,91,38,15,56,9,42,2,44,21,26,18,48,31,57,93,8, %U A244669 49,54,5,72,15,80,45,60,7,62,24,104,127,84,1,68,63,32,9 %N A244669 Denominators of (product of divisors of n / sum of divisors of n). %C A244669 Denominators of (A007955(n) / A000203(n)). %C A244669 For numerators see A244668. %F A244669 a(n) = 1 for numbers from A145551 (numbers n such that product of divisors of n / sum of divisors of n is an integer). %e A244669 a(8) = 15 because A007955(8) / A000203(8) = 64 / 15. %o A244669 (Magma)[Denominator((&*[d: d in Divisors(n)]) / (&+[d: d in Divisors(n)])): n in [1..1000]] %o A244669 (PARI) a007955(n)=if(issquare(n, &n), n^numdiv(n^2), n^(numdiv(n)/2)) ; %o A244669 a(n) = denominator(a007955(n)/sigma(n)); \\ _Michel Marcus_, Jul 05 2014 %Y A244669 Cf. A007955, A000203, A145551, A244668, A244670. %K A244669 nonn,frac %O A244669 1,2 %A A244669 _Jaroslav Krizek_, Jul 04 2014