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 A122862 #17 Jul 09 2025 04:44:35
%S A122862 2,260,650,1928,5768,36548
%N A122862 Numbers k such that (9*10^k - 11)/7 is prime.
%C A122862 All terms are of the form 2+6*i, i = 0,1,... .
%C A122862 Are there any k's such that (9*10^k - 11)/p is prime for prime p<>7?
%t A122862 Do[If[PrimeQ[(9*10^n-11)/7],Print[n]],{n,2,7220,6}]
%o A122862 (PARI) is(n)=ispseudoprime((9*10^n-11)/7) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A122862 Cf. A100275.
%K A122862 nonn,more
%O A122862 1,1
%A A122862 _Zak Seidov_, Sep 22 2006
%E A122862 a(6) from _Michael S. Branicky_, Jul 08 2025