A089257 Even numbers n such that 2n-5 is a prime of the form 4k+3.

4, 6, 8, 12, 14, 18, 24, 26, 32, 36, 38, 42, 44, 54, 56, 66, 68, 72, 78, 84, 86, 92, 98, 102, 108, 114, 116, 122, 128, 134, 138, 144, 156, 158, 168, 176, 182, 186, 192, 194, 212, 218, 222, 224, 234, 236, 242, 246, 248, 252, 254, 264, 276, 284, 288, 296, 302, 306

Offset: 1

Author

Giovanni Teofilatto, Dec 12 2003

Keywords

• easy
• nonn

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

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

Crossrefs

Cf. A002145.

Programs

Mathematica

pf4kQ[n_]:=Module[{c=2n-5},PrimeQ[c]&&IntegerQ[(c-3)/4]]; Select[Range[ 2,400,2],pf4kQ] (* Harvey P. Dale, Oct 22 2011 *)

Extensions

More terms from R. J. Mathar, Apr 22 2010