A093988 Numbers k such that 2^k + 3*k is prime.

1, 3, 5, 7, 11, 13, 35, 45, 47, 57, 87, 183, 325, 367, 447, 809, 1157, 2789, 5775, 14829, 20687, 46463, 62491

Offset

1,2

Comments

a(22) > 31410. - Jinyuan Wang, Feb 03 2020

Links

Table of n, a(n) for n=1..23.

Maple

A093988:=n->`if`(isprime(2^n+3*n), n, NULL): seq(A093988(n), n=1..10^3); # Wesley Ivan Hurt, Jan 21 2017

Mathematica

Do[ If[ PrimeQ[2^n + 3n], Print[n]], {n, 1, 5000, 2}]

Prog

(PARI) isok(n) = isprime(2^n + 3*n); \\ Michel Marcus, Jan 21 2017
(PFGW) ABC2 2^$a+3*$a
a: from 1 to 1000 // Jinyuan Wang, Feb 03 2020

Crossrefs

Cf. A082101, A086653, A094963.

Sequence in context: A155916 A038979 A179739 * A175914 A288370 A108817

Adjacent sequences: A093985 A093986 A093987 * A093989 A093990 A093991

Keyword

nonn,more

Author

Robert G. Wilson v, May 25 2004

Extensions

a(19)-a(21) from Ryan Propper, Jul 05 2005

a(22)-a(23) from Michael S. Branicky, May 19 2023

Status

approved