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 A029913 #13 Mar 08 2020 23:53:40 %S A029913 2,3,17,5,13,7,17,59,29,11,17,13,53,293,16,17,59,19 %N A029913 Start with n; if prime, stop; repeatedly sum squares of prime factors (counted with multiplicity), until reach 16 or a prime; set a(n) = 0 if no limit exists. %e A029913 9 -> 3^2 + 3^2 = 18 -> 4 + 9 + 9 = 22 -> 4 + 121 = 125 -> 25 + 25 + 25 = 75 -> 9 + 25 + 25 = 59, so a(9) = 59. %Y A029913 Cf. A029914. %K A029913 nonn,more %O A029913 2,1 %A A029913 _Dann Toliver_ %E A029913 More terms from _Michel ten Voorde_, Apr 12 2001 %E A029913 Incorrect extension reverted by _Sean A. Irvine_, Mar 08 2020