A152520 - OEIS

%I #2 Mar 30 2012 17:26:28

%S 1,3,4,8,10,11

%N 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 {n, 2^n+5^n}:{1,7}, {3,133}, {4,641}, {8,390881}, {10,9766649}, {11,48830173}.

%t Do[If[Intersection[IntegerDigits[p=2^n+5^n],{2,5}]=={},Print[{n,p}]],{n,0,2000}]

%Y Cf. A074600, A007496, A152493.

%K base,nonn

%O 1,2

%A _Zak Seidov_, Oct 25 2009