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 A123176 #10 Apr 03 2023 10:36:11 %S A123176 2,3,4,5,6,7,8,9,11,14,18,22,26,31,39,43,46,65,69,126,267,380,495,762, %T A123176 1285,1304,1364,1479,1697,4469,8135,9193,11065,11902,12923,13103, %U A123176 23396,23642,31850,77509,285228 %N A123176 Numbers n such that (2^p + 1)/3 is prime, where p is the n-th prime. %C A123176 Also prime(a(n)) are the indices of prime Jacobsthal numbers (A001045) with prime indices. Primes in the Jacobsthal sequence are listed in A049883. %H A123176 C. Caldwell's The Top Twenty, <a href="https://t5k.org/top20/page.php?id=67">Wagstaff</a>. %F A123176 a(n) = A000720( A000978(n) ). %t A123176 Select[Range[500],PrimeQ[(2^Prime[#]+1)/3]&] (* The program generates the first 23 terms of the sequence. To generate more, increase the Range constant. *) (* _Harvey P. Dale_, Mar 09 2022 *) %Y A123176 Cf. A000978, A000979, A001045, A049883, A107036, A123214. %K A123176 more,nonn %O A123176 1,1 %A A123176 _Alexander Adamchuk_, Oct 03 2006 %E A123176 Two more terms computed from A000978 by _Max Alekseyev_, Mar 03 2010