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 A337609 #16 Nov 17 2020 14:24:31 %S A337609 2,3,14,21,26,34,38,39,50,57,62,74,75,85,86,93,94,98,110,111,118,122, %T A337609 129,134,142,146,147,154,158,165,170,182,183,194,201,202,206,214,218, %U A337609 219,230,235,237,242,254,255,266,273,274,278,286,290,291,298,302,309 %N A337609 Positive integers m such that A126286^k(m) = m for some positive integer k. %C A337609 A126286^k(m) means apply A126286 to m k times. %C A337609 Equivalently, the numbers that belong to a cycle under the map x -> A126286(x). %C A337609 For any term m in this sequence, A126286(A126286(m)) = m. %C A337609 Supersequence of A017545. Moreover, this sequence can be represented as an infinite union of arithmetic progressions. %C A337609 2 and 3 are the only primes in this sequence. %H A337609 Ely Golden, <a href="/A337609/b337609.txt">Table of n, a(n) for n = 1..10000</a> %H A337609 Ely Golden, <a href="/A337609/a337609.py.txt">Python program for generating terms of this sequence</a> %e A337609 3 is a term since A126286(A126286(3)) = A126286(2) = 3. %Y A337609 Cf. A017545, A126286, A337610, A337611, A337612. %K A337609 nonn,easy %O A337609 1,1 %A A337609 _Ely Golden_, Oct 07 2020