A138931 Primes of the form (10^n-3^n)/7.

13, 139, 14251, 1428571428571428571364245156301286091

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 16 2008

Keywords

• nonn

Comments

The next term is too large to include here.

Crossrefs

Cf. A128026.

Programs

Mathematica

a={};Do[p=(10^n-3^n)/7;If[PrimeQ[p],AppendTo[a,p]],{n,1,25^2}];a
Select[Table[(10^n-3^n)/7,{n,50}],PrimeQ] (* Harvey P. Dale, Dec 18 2018 *)