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 A062593 #20 Jul 04 2021 07:52:52 %S A062593 2,13,157,43117 %N A062593 Numbers k such that 27^k - 26^k is prime. %C A062593 Terms > 1000 are often only strong pseudoprimes. %C A062593 a(5) > 10^5. - _Robert Price_, Aug 12 2012. %o A062593 (PARI) is(n)=ispseudoprime(27^n-26^n) \\ _Charles R Greathouse IV_, Jun 12 2017 %Y A062593 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062593 nonn,hard %O A062593 1,1 %A A062593 _Mike Oakes_, May 18 2001, May 19 2001 %E A062593 a(4) from _Robert Price_, Aug 12 2012