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 A057908 #12 Jan 07 2015 18:14:58
%S A057908 1,3,5,35,95,1323,24747
%N A057908 Numbers n such that 4^n - n is prime.
%C A057908 a(8) > 2*10^5. - _Robert Price_, Feb 11 2014
%t A057908 Do[ If[ PrimeQ[ 4^n - n ], Print[ n ] ], {n, 0, 3000} ]
%o A057908 (PARI) for(k=1,10^6,if(ispseudoprime(4^k-k),print1(k,", "))); /* _Joerg Arndt_, Apr 07 2013 */
%K A057908 nonn,more
%O A057908 1,2
%A A057908 _Robert G. Wilson v_, Nov 16 2000
%E A057908 a(7) from _Robert Price_, Feb 11 2014