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A089681
Numbers n such that 3n^2 - 1 is prime.
2
1, 2, 4, 6, 8, 12, 14, 18, 22, 26, 28, 30, 34, 40, 44, 48, 50, 52, 54, 58, 60, 70, 72, 74, 76, 78, 92, 96, 110, 118, 122, 136, 138, 144, 150, 154, 158, 164, 176, 182, 186, 188, 204, 210, 214, 216, 230, 232, 234, 236, 242, 248, 260, 268, 272, 274, 280, 298, 304, 308
OFFSET
1,2
REFERENCES
M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
LINKS
MATHEMATICA
Select[Range[500], PrimeQ[3#^2-1]&] (* Harvey P. Dale, Oct 09 2011 *)
PROG
(PARI) is(n)=isprime(3*n^2-1) \\ Charles R Greathouse IV, Jun 05 2017
CROSSREFS
Sequence in context: A260652 A324102 A089623 * A227308 A214294 A233578
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Jan 05 2004
EXTENSIONS
More terms from Rick L. Shepherd, May 18 2005
STATUS
approved