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 A152520 #2 Mar 30 2012 17:26:28
%S A152520 1,3,4,8,10,11
%N A152520 Numbers n such that the decimal expansion of 2^n+5^n contains no 2's and no 5's (probably 11 is the last term).
%e A152520 {n, 2^n+5^n}:{1,7}, {3,133}, {4,641}, {8,390881}, {10,9766649}, {11,48830173}.
%t A152520 Do[If[Intersection[IntegerDigits[p=2^n+5^n],{2,5}]=={},Print[{n,p}]],{n,0,2000}]
%Y A152520 Cf. A074600, A007496, A152493.
%K A152520 base,nonn
%O A152520 1,2
%A A152520 _Zak Seidov_, Oct 25 2009