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 A059762 #25 Feb 16 2025 08:32:44
%S A059762 41,1031,1451,1481,1511,1811,1889,1901,1931,3449,3491,3821,3911,5081,
%T A059762 5441,5849,6101,6131,7151,7349,7901,8969,9221,10691,10709,11171,11471,
%U A059762 11801,12101,12821,12959,13229,14009,14249,14321,14669,14741,15161
%N A059762 Initial primes of Cunningham chains of first type with length exactly 3. Primes in A059453 that survive as primes just two "2p+1 iterations", forming chains of exactly 3 terms.
%C A059762 Primes p such that {(p-1)/2, p, 2p+1, 4p+3, 8p+7} = {composite, prime, prime, prime, composite}.
%H A059762 Amiram Eldar, <a href="/A059762/b059762.txt">Table of n, a(n) for n = 1..10000</a>
%H A059762 Chris Caldwell's Prime Glossary, <a href="https://t5k.org/glossary/page.php?sort=CunninghamChain">Cunningham chains</a>.
%H A059762 Warut Roonguthai, <a href="http://web.archive.org/web/20010405230842/http://ksc9.th.com/warut/cunningham.html">Yves Gallot's Proth.exe and Cunningham Chains</a>.
%H A059762 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CunninghamChain.html">Cunningham Chain</a>.
%e A059762 41 is a term because 20 and 325 are composites, and 41, 83, and 167 are primes.
%t A059762 ipccQ[n_]:=Module[{c=(n-1)/2},PrimeQ[NestList[2#+1&,c,4]]=={False, True, True, True, False}]; Select[Prime[Range[2000]],ipccQ] (* _Harvey P. Dale_, Nov 10 2014 *)
%Y A059762 Cf. A023272, A023302, A023330, A005384, A005385, A059452, A059453, A059454, A059455, A007700.
%K A059762 nonn
%O A059762 1,1
%A A059762 _Labos Elemer_, Feb 20 2001
%E A059762 Definition corrected by _Alexandre Wajnberg_, Aug 31 2005
%E A059762 Offset corrected by _Amiram Eldar_, Jul 15 2024