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 A333610 #5 Mar 28 2020 17:45:38
%S A333610 1,2,3,4,5,11,17,47,85,227,257,919,1229,2459,4369,9839,30865,101503,
%T A333610 148157,438499,828297,2201671,3316617,11055391,35354993,140810491,
%U A333610 188991053,377982107,848170377,1704741139,6933926513
%N A333610 Least number that reaches 1 after n iterations of the infinitary totient function A091732.
%F A333610 A333609(a(n)) = n.
%t A333610 f[p_, e_] := p^(2^(-1 + Position[Reverse @ IntegerDigits[e, 2], 1])); iphi[1] = 1; iphi[n_] := Times @@ (Flatten@(f @@@ FactorInteger[n]) - 1); numiter[n_] := Length @ NestWhileList[iphi, n, # != 1 &] - 1; n = 0; seq = {}; Do[If[numiter[k] == n, AppendTo[seq, k]; n++], {k, 1, 1000}]; seq
%Y A333610 Cf. A003271, A007755, A091732, A333609.
%K A333610 nonn,more
%O A333610 0,2
%A A333610 _Amiram Eldar_, Mar 28 2020