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 A370664 #5 Feb 28 2024 13:24:36 %S A370664 0,5,11,1389,5351,6207,31173 %N A370664 Numbers k such that A176972(k) = 7^k + 7*k + 1 is prime. %C A370664 If it exists, a(8) > 50000. %o A370664 (PARI) is(n) = ispseudoprime(7^n+7*n+1) %Y A370664 Cf. A176972, A221909, A370657, A370660. %K A370664 nonn,more,hard %O A370664 1,2 %A A370664 _Hugo Pfoertner_, Feb 26 2024