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 A265938 #21 Jun 09 2024 18:06:06 %S A265938 0,1,2,3,4,5,7,10,11,14,23,31,37,42,105,106,114,137,182,212,233,313, %T A265938 621,629,1067,1570,4612,6288,20030,21843,24800,43694,179970 %N A265938 Numbers k such that 6*10^k + 91 is prime. %C A265938 For k > 1, numbers k such that the digit 6 followed by k-2 occurrences of the digit 0 followed by the digits 91 is prime (see Example section). %C A265938 a(34) > 3*10^5. %H A265938 Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/prime_difficulty.txt">Search for 60w91</a>. %e A265938 3 is in this sequence because 6*10^3+91 = 6091 is prime. %e A265938 Initial terms and associated primes: %e A265938 a(1) = 0, 97; %e A265938 a(2) = 1, 151; %e A265938 a(3) = 2, 691; %e A265938 a(4) = 3, 6091; %e A265938 a(5) = 4, 60091, etc. %t A265938 Select[Range[0, 100000], PrimeQ[6*10^# + 91] &] %o A265938 (PARI) is(n)=ispseudoprime(6*10^n + 91) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A265938 Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. %K A265938 nonn,more %O A265938 1,3 %A A265938 _Robert Price_, Apr 06 2016 %E A265938 a(33) from _Robert Price_, May 21 2019