A089238 Numbers k such that 3*k^2/2 - 1 is a prime.

2, 4, 6, 10, 14, 16, 20, 24, 26, 34, 40, 44, 54, 56, 60, 64, 70, 76, 86, 90, 104, 110, 116, 120, 124, 126, 130, 136, 140, 146, 150, 154, 164, 166, 174, 186, 194, 200, 204, 230, 240, 244, 260, 264, 286, 300, 306, 336, 346, 354, 374, 386, 394, 400, 414, 416, 420

Offset: 1

Author

Giovanni Teofilatto, Dec 22 2003

Keywords

• nonn

Comments

All terms must be even numbers. - Harvey P. Dale, Jul 03 2017

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

Crossrefs

Cf. A090686.

Programs

Mathematica

Select[Range[0,500,2],PrimeQ[(3#^2)/2-1]&] (* Harvey P. Dale, Jul 03 2017 *)

PARI

forstep(n=2,1000,2, if(isprime(3*n^2/2-1), print1(n,", "))) - Rick L. Shepherd, May 06 2008

Extensions

Corrected and extended by Rick L. Shepherd, May 06 2008