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 A110056 #8 Apr 03 2023 10:36:11 %S A110056 13,7,167,4079,47,2879,71850239,2444789759,21981381119,13357981992959, %T A110056 681004115066879,1136001594224639,16756459239477534719, %U A110056 781558105952602767359 %N A110056 Least prime that ends a complete Cunningham chain (of the first kind) of length n. %C A110056 "Complete" means that this chain is not part of a longer Cunningham chain of the first kind. %C A110056 Next term is greater than 4*10^17. %C A110056 A005602(13)-> 8181864863026139 -> ... -> a(13) = 16756459239477534719. [From _Washington Bomfim_, Oct 21 2009] %H A110056 Chris Caldwell's Prime Glossary, <a href="https://t5k.org/glossary/page.php?sort=CunninghamChain">Cunn ingham chains</a>. %e A110056 41->83->167 is a Cunningham chain of the first kind. It is complete because neither (41-1)/2 nor 2*167+1 is prime. It is the first such chain of three primes, so a(3) = 167. %Y A110056 Cf. A005384, A005385, A007700, A023272, A023302, A023330, A059452, A057326, A059455, A059761, A059762, A059763, A059764, A074313. %Y A110056 Cf. A110059 for Cunningham chains of the second kind. %Y A110056 Cf. A005602 [From _Washington Bomfim_, Oct 21 2009] %K A110056 nonn,hard %O A110056 1,1 %A A110056 _Alexandre Wajnberg_, Sep 04 2005 %E A110056 Edited and extended by _David Wasserman_, Aug 08 2006 %E A110056 a(13) and a(14) from _Washington Bomfim_, Oct 21 2009