A282669 Prime numbers p > 3 such that 2^p - 9 is prime.

5, 11, 17, 251, 563, 21011

Offset

1,1

Comments

Let W = 2^p - 9 and s = (W+7)/(2*p), then 3^s == 4 (mod W) for terms 1..6.

Links

Table of n, a(n) for n=1..6.

Mathematica

Select[Prime[Range[3, 565]], PrimeQ[2^#-9]&] (* The program generates the first five terms of the sequence. *) (* Harvey P. Dale, Aug 24 2024 *)

Prog

(PARI)
forprime(p=5, 10^5, W= 2^p-9; if(ispseudoprime(W), print1(p, ", ")))

Crossrefs

Cf. A059610.

Sequence in context: A059960 A265850 A185365 * A271655 A294135 A265851

Adjacent sequences: A282666 A282667 A282668 * A282670 A282671 A282672

Keyword

nonn,more

Author

Dmitry Ezhov, Mar 07 2017

Status

approved