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 A299374 #19 Nov 24 2024 03:27:21 %S A299374 2,8,252,1184,1308 %N A299374 Numbers k such that k * 11^k - 1 is prime. %C A299374 a(6) > 500000. %H A299374 Steven Harvey, <a href="http://harvey563.tripod.com/GeneralizedWoodallPrimes.txt">Generalized Woodall Search</a> %H A299374 Wikipedia, <a href="https://en.wikipedia.org/wiki/Woodall_number">Woodall number</a> %t A299374 Select[Range[1, 10000], PrimeQ[n*11^n-1] &] %o A299374 (PARI) for(n=1, 10000, if(ispseudoprime(n*11^n-1), print1(n", "))) %o A299374 (Magma) [n: n in [1..10000] |IsPrime(n*11^n-1)]; %Y A299374 Numbers n such that n * b^n - 1 is prime: A008864 (b=1), A002234 (b=2), A006553 (b=3), A086661 (b=4), A059676 (b=5), A059675 (b=6), A242200 (b=7), A242201 (b=8), A242202 (b=9), A059671 (b=10), this sequence (b=11), A299375 (b=12), A299376 (b=13), A299377 (b=14), A299378 (b=15), A299379 (b=16), A299380 (b=17), A299381 (b=18), A299382 (b=19), A299383 (b=20). %K A299374 nonn,more,hard %O A299374 1,1 %A A299374 _Tim Johannes Ohrtmann_, Feb 08 2018