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 A110059 #11 Apr 03 2023 10:36:11 %S A110059 11,13,5,17041,24481,12338881,1065601,1985902081,219416417281, %T A110059 105230562877441,1422461638625281,444124661486837761, %U A110059 3105111850422067201 %N A110059 Smallest prime ending a complete Cunningham chain of the second kind (2x-1) of length n. %C A110059 "Complete" means that the chain is not part of a longer chain. %C A110059 A005603 has the first prime of each chain. %H A110059 Chris Caldwell's Prime Glossary, <a href="https://t5k.org/glossary/page.php?sort=CunninghamChain">Cunningham chains</a>. %e A110059 a(4)=17041 because 2131,4261,8521,17041 are prime, but the preceding and following numbers (1066,34081) are not. %Y A110059 Cf. A005382, A005384, A057326, A059761, A005603. %K A110059 nonn %O A110059 1,1 %A A110059 _Alexandre Wajnberg_, Sep 04 2005 %E A110059 Some terms computed by Gilles Sadowski. %E A110059 Edited by _Don Reble_, May 16 2006