A122042 Numbers n such that (2^n+n)/(n+2) is prime.

13, 19, 55, 469, 3385

Offset: 1

Author

Zak Seidov, Sep 14 2006

Keywords

• more
• nonn

Comments

All terms are also in A081765 = numbers n such that n+2 divides 2^(n-1)-1.

Crossrefs

Cf. A081765.

Programs

Mathematica

Do[If[PrimeQ[(2^n+n)/(n+2)],Print[n]],{n,1,5000}]

PARI

is(n)=ispseudoprime((2^n+n)/(n+2)) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(5) from Alexander Adamchuk, Sep 17 2006