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 A037931 #8 Aug 11 2024 14:41:31 %S A037931 30,2,3,5,5,47,547 %N A037931 Trajectory of 30 under prime factor concatenation procedure. %H A037931 P. De Geest, <a href="https://www.worldofnumbers.com/topic1.htm">Home Primes</a> %Y A037931 Cf. A037273. %K A037931 fini,full,nonn,tabf,base %O A037931 0,1 %A A037931 _Jeff Burch_ %E A037931 Edited by _Charles R Greathouse IV_, Apr 30 2010