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 A337612 #9 Nov 01 2020 01:36:44
%S A337612 1,6,10,15,20,21,35,38,42,45,52,58,63,66,68,74,76,77,78,84,85,88,92,
%T A337612 99,110,116,117,124,130,133,143,146,153,164,171,187,189,198,208,224,
%U A337612 228,232,238,246,247,255,261,266,268,272,273,279,282,284,285,304,312
%N A337612 Positive integers m such that A126289^k(m) = m for some positive integer k.
%C A337612 A126289^k(m) means apply A126289 to m k times.
%C A337612 Equivalently, the numbers that belong to a cycle under the map x -> A126289(x).
%C A337612 There are no primes in this sequence.
%H A337612 Ely Golden, <a href="/A337612/b337612.txt">Table of n, a(n) for n = 1..10000</a>
%H A337612 Ely Golden, <a href="/A337612/a337612.py.txt">Python program for (naïvely) generating terms of this sequence</a>
%F A337612 For any term m, gcd {m, A126289(m), A126289(A126289(m)), ...} = A052126(m).
%e A337612 6 is a term since A126289(A126289(6)) = A126289(10) = 6.
%Y A337612 Cf. A052126, A126289, A337609, A337610, A337611.
%K A337612 nonn
%O A337612 1,2
%A A337612 _Ely Golden_, Oct 06 2020