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 A245241 #25 Nov 16 2014 00:44:25 %S A245241 0,1,4,9,99,412,2633,5093,5632,28233,36780,47084,53572 %N A245241 Integers n such that 6 * 7^n + 1 is prime. %C A245241 All terms correspond to verified primes, that is, not merely probable primes. %C A245241 a(14) > 2*10^5. %e A245241 4 is in this sequence because 6 * 7^4 + 1 = 14407, which is prime. %t A245241 Select[Range[0,200000], PrimeQ[6 * 7^# + 1] &] %Y A245241 Cf. A003307, A002235, A046865, A079906, A001771, A005541, A056725, A046867, A079907. %Y A245241 Cf. A005537, A005538, A005539, A216889, A216890, A247260. %K A245241 nonn,more %O A245241 1,3 %A A245241 _Robert Price_, Nov 14 2014