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 A062639 #19 Jul 04 2021 09:02:07 %S A062639 19,83,1091,20117 %N A062639 Numbers k such that 73^k - 72^k is prime. %C A062639 Terms greater than 1000 are often only strong pseudoprimes. %C A062639 a(5) > 10^5. - _Robert Price_, Apr 21 2014 %o A062639 (PARI) is(n)=ispseudoprime(73^n-72^n) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A062639 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062639 nonn,hard %O A062639 1,1 %A A062639 _Mike Oakes_, May 18 2001, May 19 2001 %E A062639 a(4) from _Robert Price_, Apr 21 2014 (Computer run by Adam Marciniec)