A236477 Numbers k such that k^3 - k + 1 is prime.

2, 4, 6, 7, 10, 11, 14, 15, 19, 21, 22, 25, 26, 31, 35, 39, 41, 42, 45, 50, 52, 54, 57, 62, 75, 77, 84, 85, 87, 90, 92, 95, 99, 101, 102, 106, 111, 116, 120, 125, 129, 130, 132, 134, 136, 139, 140, 141, 147, 155, 167, 169, 176, 189, 195, 202, 221, 230, 237

Offset: 1

Author

Derek Orr, Jan 26 2014

Keywords

• nonn

Examples

			26^3 - 26 + 1 = 17551 is prime. So 26 is a member of this sequence.
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A049407, A126421, A236478.

Programs

Mathematica

Select[Range[250],PrimeQ[#^3-#+1]&] (* Harvey P. Dale, Dec 06 2017 *)

PARI

s=[]; for(n=1, 500, if(isprime(n^3-n+1), s=concat(s, n))); s \\ Colin Barker, Jan 27 2014

Python

import sympy
from sympy import isprime
{print(n) for n in range(10**3) if isprime(n**3-n+1)}

Extensions

More terms from Colin Barker, Jan 27 2014