A111149 - OEIS

A111149

Numbers n such that 5*n^2 + 9 is prime.

2, 4, 10, 16, 26, 28, 38, 40, 44, 46, 58, 70, 80, 82, 88, 94, 98, 110, 116, 128, 130, 136, 140, 142, 154, 164, 178, 194, 200, 208, 212, 214, 220, 224, 236, 248, 250, 254, 256, 268, 278, 284, 298, 310, 320, 322, 332, 334, 338, 362, 392, 406, 422, 424, 458, 460

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

If n=154 then 5*n^2 + 9 = 118589 (prime).

MATHEMATICA

Select[Range[500], PrimeQ[5*#^2 + 9] &] (* Stefan Steinerberger, Feb 26 2006 *)

PROG

(PARI) is(n)=isprime(5*n^2+9) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS