A090670 Odd numbers k such that 2*k-3 is a prime of the form 4*j+3.

3, 5, 7, 11, 13, 17, 23, 25, 31, 35, 37, 41, 43, 53, 55, 65, 67, 71, 77, 83, 85, 91, 97, 101, 107, 113, 115, 121, 127, 133, 137, 143, 155, 157, 167, 175, 181, 185, 191, 193, 211, 217, 221, 223, 233, 235, 241, 245, 247, 251, 253, 263, 275, 283, 287, 295, 301, 305

Offset: 1

Author

Giovanni Teofilatto, Dec 17 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

• Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A087915, A002145.

Cf. A050415 (primes of the form 2^k-3).

Programs

Mathematica

okQ[n_]:=Module[{x=2n-3},PrimeQ[x]&&IntegerQ[(x-3)/4]]; Select[Range[1,315,2],okQ]  (* Harvey P. Dale, Jan 12 2011 *)

Formula

a(n) = A087915(n)+3.

Extensions

Offset changed from 0 to 1 by Vincenzo Librandi, Dec 13 2011