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A126961 Primes p such that (3p)^2 + 2 is not prime. 1
2, 17, 23, 29, 31, 43, 47, 53, 59, 61, 67, 71, 89, 97, 109, 113, 127, 131, 137, 157, 163, 173, 179, 181, 193, 197, 199, 211, 223, 229, 239, 241, 257, 263, 271, 277, 281, 283, 293, 307, 313, 317, 331, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

Garath A. Jones and Mary Jones, Elementary Number Theory, Springer - Verlag London, 1998; p. 35, Exercise 2.17.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime[Range[100]], ! PrimeQ[(3#)^2 + 2] &] (* Harvey P. Dale, Jun 14 2011 *)

PROG

(PARI) g(n) = forprime(x=0, n, y=9*x^2+2; if(!isprime(y), print1(x", ")))

(MAGMA) [p: p in PrimesUpTo(500) | not IsPrime(9*p^2+2)]; // Vincenzo Librandi, Apr 17 2013

CROSSREFS

Sequence in context: A309055 A157191 A006029 * A106622 A040992 A049550

Adjacent sequences:  A126958 A126959 A126960 * A126962 A126963 A126964

KEYWORD

nonn,easy

AUTHOR

Cino Hilliard, Mar 19 2007

STATUS

approved

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Last modified October 20 02:54 EDT 2019. Contains 328244 sequences. (Running on oeis4.)