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 A217351 #26 Sep 19 2024 11:53:37 %S A217351 1,2,3,4,6,21,24,27,30,54,70,126,369,435,612,787,1275,2155,2436,5734, %T A217351 6016,16107,25786,34266,38841,45834,46584 %N A217351 Numbers k such that 6^k + 7 is prime. %t A217351 Select[Range[10000], PrimeQ[6^# + 7] &] %o A217351 (PARI) is(n)=ispseudoprime(6^n+7) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A217351 Cf. A145106, A217352. %Y A217351 Cf. A104115 (associated primes). %K A217351 nonn,more,hard %O A217351 1,2 %A A217351 _Vincenzo Librandi_, Oct 02 2012 %E A217351 a(20)-a(21) from _Bruno Berselli_, Oct 04 2012 %E A217351 a(22)-a(23) from _Michael S. Branicky_, Apr 30 2023 %E A217351 a(24)-a(27) from _Michael S. Branicky_, Sep 19 2024