A077375 Numbers k such that 2^k + prime(k) is prime.

2, 3, 4, 5, 12, 13, 14, 23, 57, 106, 226, 227, 311, 373, 1046, 1298, 1787, 1952, 2130, 2285, 2670, 3254, 3642, 4369, 13559, 33418, 66830, 213810

Offset

1,1

Comments

All terms < 5000 correspond to certified primes (Primo 2.2.0 beta). - Ryan Propper, Aug 08 2005

Links

Table of n, a(n) for n=1..28.

H. Lifchitz, Mersenne and Fermat primes field

Example

2^12 + prime(12) = 4096 + 43 = 4139 is a prime, so 12 is a term.

Crossrefs

Corresponding prime(k) are in A242944.

Cf. A078583, A078686.

Sequence in context: A281597 A039007 A050745 * A328209 A250049 A132027

Adjacent sequences: A077372 A077373 A077374 * A077376 A077377 A077378

Keyword

nonn,more

Author

Jason Earls, Nov 30 2002

Extensions

a(25)-a(26) from Ryan Propper, Aug 08 2005

a(27) from Henri Lifchitz added by Jason Earls, Jan 12 2008

a(28) from Michael S. Branicky, Jun 01 2025

Status

approved