A141489 Numbers k such that k^2 + k + 257 is prime.

0, 2, 3, 4, 7, 9, 10, 11, 13, 14, 17, 18, 20, 21, 23, 24, 25, 27, 28, 30, 31, 34, 37, 41, 42, 44, 48, 49, 51, 53, 56, 59, 60, 63, 65, 66, 67, 69, 70, 73, 74, 77, 79, 80, 81, 83, 88, 90, 91, 93, 94, 95, 100, 101, 104, 107, 111, 114, 115, 116, 119, 122, 125, 129, 135, 137

Offset: 1

Author

Parthasarathy Nambi, Aug 09 2008

Keywords

• nonn

Examples

			If k=0, then k^2 + k + 257 = 257 (prime).
If k=100, then k^2 + k + 257 = 10357 (prime).
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A002837, A056561, A133157, A133160.

Programs

Magma

[n: n in [0..5000] |IsPrime(n^2+n+257)]; // Vincenzo Librandi, Nov 25 2010

Mathematica

Select[Range[0,200],PrimeQ[#^2+#+257]&] (* Harvey P. Dale, Jun 07 2016 *)

PARI

isok(n) = isprime(n^2+n+257); \\ Michel Marcus, Mar 12 2017

Extensions

More terms from Vincenzo Librandi, Mar 25 2010