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 A062617 #17 Jul 04 2021 08:42:44 %S A062617 2,7,139,383,1187,5857,41281 %N A062617 Numbers k such that 51^k - 50^k is prime. %C A062617 Terms greater than 1000 are often only strong pseudoprimes. %C A062617 a(8) > 10^5. - _Robert Price_, Feb 28 2013 %o A062617 (PARI) is(n)=ispseudoprime(51^n-50^n) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A062617 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062617 nonn,hard %O A062617 1,1 %A A062617 _Mike Oakes_, May 18 2001, May 19 2001 %E A062617 a(7) from _Robert Price_, Feb 28 2013