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 A113939 #12 Jul 22 2021 01:57:37 %S A113939 1,300118,2250885,5294800,76336260,141483384,242375035,453280968, %T A113939 456345036,461356896,478240392,537375930,1139523375,1180718238, %U A113939 1227111595,1599634410,5043835125,5229921340,5610392513,6087775939,6376494509,11038341720,11044670824 %N A113939 Numbers k such that sigma(k) and phi(k) are both perfect cubes. %C A113939 phi(k) = A000010(k) is the Euler totient function, while sigma(k) = A000203(k) is the sum of divisors of k. %C A113939 Intersection of A020477 and A039771. - _Michel Marcus_, Jan 04 2014 %e A113939 sigma(2250885) = 168^3 and phi(2250885) = 96^3. %o A113939 (PARI) for(n=1, 10^9, if(ispower(eulerphi(n),3), if(ispower(sigma(n),3), print1(n ", ")))) \\ _Donovan Johnson_, Jan 04 2014 %Y A113939 Cf. A000010, A000203. %K A113939 nonn %O A113939 1,2 %A A113939 _Giovanni Resta_, Jan 31 2006 %E A113939 a(7)-a(20) from _Donovan Johnson_, Feb 06 2010 %E A113939 a(21)-a(23) from _Donovan Johnson_, Jan 04 2014