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 A378929 #15 Dec 16 2024 17:27:38
%S A378929 0,1,1,3,1,0,1,2,2,0,1,2,1,0,3,4,1,2,1,4,3,0,1,2,1,0,4,4,1,3,1,6,3,0,
%T A378929 1,4,1,0,3,2,1,3,1,4,4,0,1,5,1,0,3,4,1,4,1,2,3,0,1,2,1,0,4,8,1,3,1,4,
%U A378929 3,0,1,1,1,0,0,4,1,3,1,3,1,0,1,2,1,0,3,2
%N A378929 Number of steps it takes for the chain of f(n) = n * d(n) / gcd(n, d(n))^2 to reach a cycle from a starting number n.
%C A378929 It is conjectured that every number n eventually ends up in a cycle.
%H A378929 Viliam Furík, <a href="/A378929/b378929.txt">Table of n, a(n) for n = 1..10000</a>
%t A378929 f[n_] := Module[{d = DivisorSigma[0, n]}, n*d/GCD[n, d]^2]; a[n_] := Module[{s = NestWhileList[f, n, UnsameQ, All]}, FirstPosition[s, s[[-1]]][[1]] - 1]; Array[a, 100] (* _Amiram Eldar_, Dec 16 2024 *)
%Y A378929 Cf. A000005, A378930.
%K A378929 nonn
%O A378929 1,4
%A A378929 _Viliam Furík_, Dec 11 2024