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 A062597 #16 Jul 04 2021 07:53:53 %S A062597 2,3,5,211 %N A062597 Numbers k such that 31^k - 30^k is prime. %C A062597 Terms > 1000 are often only strong pseudoprimes. %C A062597 a(5) > 10^5 - _Robert Price_, Nov 14 2012 %o A062597 (PARI) is(n)=ispseudoprime(31^n-30^n) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A062597 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062597 nonn,hard %O A062597 1,1 %A A062597 _Mike Oakes_, May 18 2001, May 19 2001