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 A370660 #5 Feb 28 2024 13:24:41 %S A370660 1,4,36,160,342,1086,2094,11524 %N A370660 Numbers k such that (7^k + 7*k)/7 is prime. %C A370660 If it exists, a(11) > 50000. %o A370660 (PARI) is(n) = ispseudoprime(7^(n-1)+n) %Y A370660 Cf. A221909, A226199, A370657. %Y A370660 Cf. A370190, A370661. %K A370660 nonn,hard,more %O A370660 1,2 %A A370660 _Hugo Pfoertner_, Feb 24 2024