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 A063106 #5 Dec 15 2017 17:35:19 %S A063106 2,5,17,43,887,522956339, %T A063106 20935051082417771847631371547939998232420940393 %N A063106 Primes of form !n + 2n - 1. %o A063106 (PARI) for(n=1,50,x=sum(k=0,n-1,k!)+(2*n-1); if(isprime(x),print(x))) %Y A063106 Cf. A003422. %K A063106 nonn %O A063106 1,1 %A A063106 _Jason Earls_, Aug 08 2001