A268211 Numbers n of the form 2^k + 1 such that n + k is a prime q (for k >= 0).

2, 5, 65, 110427941548649020598956093796432407239217743554726184882600387580788737

Offset

1,1

Comments

Subsequence of A000051.

Corresponding values of numbers k are in A100359 (numbers n such that 2^n+n+1 is prime).

Corresponding values of primes q are in A061421 (primes of the form 2^n+n+1).

Links

Table of n, a(n) for n=1..4.

Formula

a(n) = A061421(n) - A100359(n).

Example

65 = 2^6 + 1 is a term because 65 + 6 = 71 (prime).

Mathematica

2^# + 1 &@ Select[Range[0, 600], PrimeQ[2^# + # + 1] &] (* Michael De Vlieger, Jan 29 2016 *)

Prog

(Magma) [2^n + 1: n in [0..600] | IsPrime(2^n + n + 1)]

Crossrefs

Cf. A061421, A100359, A268209.

Sequence in context: A350956 A086560 A305292 * A246280 A333165 A374674

Adjacent sequences: A268208 A268209 A268210 * A268212 A268213 A268214

Keyword

nonn

Author

Jaroslav Krizek, Jan 28 2016

Status

approved