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 A226073 #8 Jan 16 2023 21:41:08 %S A226073 1,4,148,5821348,13748537282247342677718148, %T A226073 49900608324196518198677680899235165296598423281799348 %N A226073 Numbers k such that triangular(k)-1 is a square and triangular(k)+1 is a prime number. %C A226073 a(7) has 191 decimal digits: 314305920...194453348. %C A226073 Corresponding primes and roots of squares: A226072 and A226074. %Y A226073 Cf. A226069-A226074. %K A226073 nonn %O A226073 1,2 %A A226073 _Alex Ratushnyak_, May 25 2013