A205796 Numbers n such that 4*17^n - 1 is prime.

1, 9, 33, 69, 427, 1009, 2667

Offset: 1

Author

José María Grau Ribas, Jan 31 2012

Keywords

• nonn

Crossrefs

Cf. A180431 (numbers n such that 4*17^n + 1 is prime).

Cf. A205521 (numbers n such that 4*11^n - 1 is prime).

Cf. A046865 (numbers n such that 4*5^n - 1 is prime).

Cf. A005540 (numbers n such that 4*3^n - 1 is prime).

Programs

Mathematica

Table[If[PrimeQ[4*17^n-1],Print[n];n],{n,1,20000}]

PARI

is(n)=ispseudoprime(4*17^n-1) \\ Charles R Greathouse IV, Jun 13 2017