1,2

Do[ If[ PrimeQ[ ToExpression[ StringReverse[ ToString[7^n] ] ] ], Print[n] ], {n, 1, 2500} ]

Cf. A057708.

Sequence in context: A130163 A002167 A154268 this_sequence A138321 A033165 A136739

Adjacent sequences: A058991 A058992 A058993 this_sequence A058995 A058996 A058997

nonn,base

Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 17 2001