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 A266582 #16 May 03 2024 07:45:10 %S A266582 1,2,4,9,13,14,16,46,99,112,116,127,146,208,512,848,1132,2167,2482, %T A266582 2666,3625,14410,16567,21529,26272,69554,69602 %N A266582 Numbers k such that (265*10^k - 7)/3 is prime. %C A266582 For k > 0, numbers k such that the digits 88 followed by k-1 occurrences of the digit 3 followed by the digit 1 is prime (see Example section). %C A266582 a(28) > 10^5. %H A266582 Makoto Kamada, <a href="https://stdkmd.net/nrr">Factorization of near-repdigit-related numbers</a>. %H A266582 Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/prime_difficulty.txt">Search for 883w1</a>. %e A266582 4 is in this sequence because (265*10^4 - 7)/3 = 883331 is prime. %e A266582 Initial terms and associated primes: %e A266582 a(1) = 1, 881; %e A266582 a(2) = 2, 8831; %e A266582 a(3) = 4, 883331l %e A266582 a(4) = 9, 88333333331; %e A266582 a(5) = 13, 883333333333331, etc. %t A266582 Select[Range[0, 100000], PrimeQ[(265*10^# - 7)/3] &] %o A266582 (PARI) is(n)=ispseudoprime((265*10^n-7)/3) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A266582 Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. %K A266582 nonn,more %O A266582 1,2 %A A266582 _Robert Price_, Jul 10 2016