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 A038524 #19 Aug 05 2021 01:27:52 %S A038524 8,24,28,34,50,52,58,71,77,163,197,235,238,319,570,669,949,958,1211, %T A038524 1305 %N A038524 Numbers k such that the k-th Fibonacci number is composite and the concatenation of its prime factors (written in base 10 in ascending order) is prime. %H A038524 Blair Kelly, <a href="http://mersennus.net/fibonacci/">Fibonacci and Lucas Factorizations</a>. %e A038524 F(24) = 46368 = 2^5 * 3^2 * 7 * 23 is composite and the concatenation 2222233723 is prime, so 24 is in the sequence. %Y A038524 Cf. A000045, A037276, A038526. %K A038524 nonn,base,hard,more %O A038524 1,1 %A A038524 _Jeff Burch_ %E A038524 More terms from _Jens Kruse Andersen_, Jan 05 2003 %E A038524 a(17)-a(18) from _Ryan Propper_, May 29 2006 %E A038524 a(19)-a(20) from _Sean A. Irvine_, Jan 16 2021