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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).
0
1, 3, 4, 8, 10, 11
OFFSET
1,2
EXAMPLE
{n, 2^n+5^n}:{1,7}, {3,133}, {4,641}, {8,390881}, {10,9766649}, {11,48830173}.
MATHEMATICA
Do[If[Intersection[IntegerDigits[p=2^n+5^n], {2, 5}]=={}, Print[{n, p}]], {n, 0, 2000}]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Zak Seidov, Oct 25 2009
STATUS
approved