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 A037938 #8 Aug 11 2024 14:41:31 %S A037938 42,2,3,7,3,79,379 %N A037938 Trajectory of 42 under prime factor concatenation procedure. %H A037938 P. De Geest, <a href="https://www.worldofnumbers.com/topic1.htm">Home Primes</a> %Y A037938 Cf. A037273. %K A037938 fini,full,nonn,tabf,base %O A037938 0,1 %A A037938 _Jeff Burch_ %E A037938 Edited by _Charles R Greathouse IV_, Apr 30 2010