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 A171411 #15 May 15 2025 11:11:26 %S A171411 0,1,2,4,5,8,27,165,230,237,369,485,628,875,964,1419,4083 %N A171411 Numbers k such that 1 + 5*10^k + 100^k is prime. %C A171411 No more terms up to k=7600. The value corresponding to 4083 was certified prime with WinPFGW. %C A171411 a(18) > 30000. - _Michael S. Branicky_, May 15 2025 %H A171411 Chris K. Caldwell, <a href="https://primes.utm.edu/primes/search.php?Description=%5E10%5E%25%2B5*10%5E%25%2B1&OnList=all&Number=20&Style=HTML">Prime Pages, Database Search Output</a> %o A171411 (PARI) is(n)=ispseudoprime(1+5*10^n+100^n) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A171411 Cf. A171376, A171459, A171514, A171554. %K A171411 nonn,more %O A171411 1,3 %A A171411 _Jason Earls_, Dec 08 2009