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 A228238 #8 Nov 04 2013 14:40:04
%S A228238 2,5,17,109,257,65537,3294173,145800001,210827009,13816758796289,
%T A228238 167772160000000001,2844673747342852097,3874204890000000001,
%U A228238 498062089990157893633,15191686954694985266495489,355271367880050092935562133789062501
%N A228238 Primes of the form x^x * y^y + 1.
%t A228238 nn = 40; Join[{2}, Select[Rest[Union[Flatten[Table[x^x*y^y + 1, {x, nn}, {y, x, nn}]]]], # <= nn^nn + 1 && PrimeQ[#] &]] (* _T. D. Noe_, Nov 04 2013 *)
%Y A228238 Cf. A000040, A156223.
%K A228238 nonn
%O A228238 1,1
%A A228238 _Alex Ratushnyak_, Nov 02 2013