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 A226281 #16 Jun 17 2013 06:32:52 %S A226281 2,2,2,2,58,440,18248,2024098,4263330280,22836544460,40728071843930 %N A226281 Least number k such that 3^(2^i) + k is prime for i = 0,1,..,n-1. %C A226281 Generalized Fermat primes of the form b^(2^i) + k. %e A226281 a(5) = 58 because k = 58 is the minimal k such that N = 3^(2^i) + k is prime for i = 0, 1, 2 ,3 ,4; N = 61, 67, 139, 6619, 43046779. But 3^(2^5) + 58 is divisible by 37 and three other primes. %Y A226281 Cf. A129613, A225560. %K A226281 nonn,more %O A226281 1,1 %A A226281 _Robin Garcia_, Jun 02 2013 %E A226281 a(11) from _Giovanni Resta_, Jun 17 2013