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 A364080 #12 Jan 05 2024 15:58:05 %S A364080 1,2,53,183,1281,1300,8041,29936,72820 %N A364080 Numbers k such that (20^k - 1)^2 - 2 is prime. %C A364080 Such primes are sometimes called Carol primes of base 20. %H A364080 Prime-Wiki, <a href="https://www.rieselprime.de/ziki/Carol-Kynea_prime">Carol-Kynea prime</a>. %H A364080 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Near-SquarePrime.html">Near-Square Prime</a>. %o A364080 (PARI) for(k=1,1200,ispseudoprime((20^k-1)^2-2)&&print1(k,", ")) %Y A364080 Cf. A091515 (b=2), A100901 (b=6), A100903 (b=10), A364076 (b=12), A100905 (b=14), A364078 (b=18), A100907 (b=22). %Y A364080 Cf. A364081. %K A364080 nonn,hard,more %O A364080 1,2 %A A364080 _Jeppe Stig Nielsen_, Jul 03 2023