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 A109397 #18 Oct 12 2024 01:39:58 %S A109397 0,6,10,11,102,146,296,1415,2324,4374,12590 %N A109397 Numbers k such that 22 * 10^k + 1 is prime. %C A109397 All terms have been certified. Primality proof for the largest: PFGW Version 1.2.0 for Windows [FFT v23.8] Primality testing 22*10^12590+1 [N-1, Brillhart-Lehmer-Selfridge] Running N-1 test using base 3 Calling Brillhart-Lehmer-Selfridge with factored part 69.89% 22*10^12590+1 is prime! (47.5292s+0.3107s) %C A109397 No more terms up to 31000. %C A109397 No more terms up to 50000. - _Michael S. Branicky_, Oct 11 2024 %o A109397 (PARI) is(n)=ispseudoprime(22*10^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A109397 Cf. A056807. %K A109397 more,nonn %O A109397 1,2 %A A109397 _Jason Earls_, Aug 26 2005 %E A109397 0 added by _Arkadiusz Wesolowski_, Oct 27 2011