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 A201133 #6 Mar 30 2012 18:36:00
%S A201133 1,3,3,23,7,3,3,5,7,59,15,35,45,23,3,5,45,57,15,5,49,17,87,105,45,5,
%T A201133 21,45,43,129,3,243,57,39,57,23,21,53,25,77,15,95,87,137,33,21,51,113,
%U A201133 49,27,7,371,45,417,51,275,253,87,75,473,109,35,229,237,253
%N A201133 Least k such that (5^n + k)*5^n + 1 is a prime number.
%t A201133 Table[k = 0; While[!PrimeQ[(5^n + k)*5^n + 1], k++]; k, {n, 85}]
%Y A201133 Cf. A191617, A200920.
%K A201133 nonn
%O A201133 1,2
%A A201133 _Michel Lagneau_, Nov 27 2011