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 A373739 #26 Jun 19 2024 02:02:20 %S A373739 1,4,16,576 %N A373739 a(n) is the smallest number that is in a cycle of length n when iterating x <- phi(sigma(x)). %C A373739 Terms in a cycle are distinct, i.e., going twice around a cycle of length 3 is not considered a cycle of length 6. %C A373739 Other terms: a(5) <= 339026688000000, a(6) = 1800, a(8) <= 12959170560000, a(9) = 113218560, a(11) = 326592, a(12) = 5033164800, a(15) = 40255488, a(18) <= 150493593600, a(21) = 12227604480, a(22) <= 1316603904000. %e A373739 16 -> 24 -> 30 -> 16, 16 is the smallest member of any cycle of length 3, so a(3)=16. %Y A373739 Cf. A062401, A095955, A095956, A373435, A373453, A373454. %K A373739 nonn,more,hard %O A373739 1,2 %A A373739 _Jud McCranie_, Jun 15 2024