A063791 Numbers k such that 2^(k+1) - k - 2 is prime.

3, 9, 13, 15, 25, 49, 55, 69, 115, 2071, 6249, 13669, 14215, 14625, 396127

Offset

1,1

References

Dean Hickerson, personal communication.

Links

Table of n, a(n) for n=1..15.

Formula

a(n) = A099439(n) - 1. - Hugo Pfoertner, Jul 24 2019

Prog

(PARI) for(n=1, 5000, if(isprime(2^(n+1)-n-2), print(n)))

Crossrefs

Cf. A099439.

Sequence in context: A193927 A111230 A046865 * A077791 A176393 A345460

Adjacent sequences: A063788 A063789 A063790 * A063792 A063793 A063794

Keyword

nonn,more,changed

Author

Jason Earls, Aug 17 2001

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

a(15) from Karsten Bonath, Jun 07 2018

Status

approved