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 A171431 #7 Feb 25 2020 05:35:18 %S A171431 2,379,389,9559969,9559999,9560119,9560149,514274011,3779851261, %T A171431 204475055129,81744303090431,241849345578327127,241849345578334537, %U A171431 241849345578337111,241849345578359263,241849345578372913,241849345578373303,97199410027250043229,97199410027250048629,97199410027250052679 %N A171431 Primes that are congruent to 4 mod n, where n is the index of the prime. %t A171431 Prime@ Select[Range[10^6], Mod[Prime[#] - 4, #] == 0 &] (* _Giovanni Resta_, Feb 25 2020 *) %Y A171431 Cf. A023146, A048891, A171430. %K A171431 nonn %O A171431 1,1 %A A171431 _Vladimir Joseph Stephan Orlovsky_, Dec 08 2009 %E A171431 Missing a(1) and a(8)-a(20) from _Giovanni Resta_, Feb 23 2020