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 A038531 #10 Jun 27 2021 07:58:29 %S A038531 79,5927,7333,10139,14951,22769,443117,541133,593143,727169,739171, %T A038531 941207,1103237,1213253,1367279,1447291,1511303,1553309,1667329, %U A038531 2011381,2129399,2213411,2237413,2267417,2287423,2339429,2609471 %N A038531 Primes that are concatenations of k-th prime and k-th composite. %Y A038531 Cf. A038532. Primes in A038530. %K A038531 nonn,base %O A038531 1,1 %A A038531 Vasiliy Danilov (danilovv(AT)usa.net), Jul 14 1998 %E A038531 Edited by _Charles R Greathouse IV_, Apr 28 2010