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 A062637 #16 Jul 04 2021 08:54:36 %S A062637 47,139,227,2339,4919,21319 %N A062637 Numbers k such that 71^k - 70^k is prime. %C A062637 Terms greater than 1000 are often only strong pseudoprimes. %C A062637 a(7) > 10^5. - _Robert Price_, Feb 17 2014 %o A062637 (PARI) is(n)=ispseudoprime(71^n-70^n) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A062637 Cf. A000043, A057468, A059801, A059802, A062572-A062666. %K A062637 nonn,hard %O A062637 1,1 %A A062637 _Mike Oakes_, May 18 2001, May 19 2001 %E A062637 a(6) from _Robert Price_, Feb 17 2014