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 A257790 #23 Dec 09 2024 14:20:37 %S A257790 0,1,2,5,11,28,65,72,361,479,494,599,1062,1094,1193,2827,3271,3388, %T A257790 3990,4418,11178,16294,25176,42500,68320,85698,145259,159119,169771, %U A257790 252665,412051 %N A257790 Numbers k such that 6*5^k - 1 is prime. %C A257790 All terms correspond to verified primes, that is, not merely probable primes. %t A257790 Select[Range[0, 10000], PrimeQ[6*5^# - 1] &] %o A257790 (Magma) [n: n in [0..2*10^3] | IsPrime(6*5^n-1)]; // _Vincenzo Librandi_, May 09 2015 %o A257790 (PARI) is(n)=ispseudoprime(6*5^n-1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A257790 Cf. A143279. %K A257790 nonn,hard,more %O A257790 1,3 %A A257790 _Robert Price_, May 08 2015 %E A257790 a(30) from _Riley Fisher_, Sep 20 2024 %E A257790 a(31) from _Riley Fisher_, Dec 09 2024