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 A037920 #13 Jun 15 2022 15:54:34
%S A037920 8,2,2,2,2,3,37,3,19,41,3,3,3,7,13,13,3,11123771,7,149,317,941,229,
%T A037920 31219729,11,2084656339,3,347,911,118189,11,613,496501723,97,130517,
%U A037920 917327,53,1832651281459,3,3,3,11,139,653,3863,5107
%N A037920 Trajectory of 8 under prime factor concatenation procedure.
%H A037920 Patrick De Geest, <a href="http://www.worldofnumbers.com/topic1.htm">Home Primes</a>
%o A037920 (Python)
%o A037920 from sympy import factorint
%o A037920 def iterate(n):
%o A037920 flst, f = [n], sorted(factorint(n, multiple=True))
%o A037920 while len(f) > 1:
%o A037920 flst += f
%o A037920 f = sorted(factorint(int("".join(map(str, f))), multiple=True))
%o A037920 return flst
%o A037920 print(iterate(8)) # _Michael S. Branicky_, Aug 02 2021
%Y A037920 Cf. A037273, A006919.
%K A037920 fini,full,nonn,tabf,base
%O A037920 0,1
%A A037920 _Jeff Burch_
%E A037920 Edited by _Charles R Greathouse IV_, Apr 30 2010