A089193 Odd numbers n such that 2*n-7 is a prime of the form 4*k+3.

5, 7, 9, 13, 15, 19, 25, 27, 33, 37, 39, 43, 45, 55, 57, 67, 69, 73, 79, 85, 87, 93, 99, 103, 109, 115, 117, 123, 129, 135, 139, 145, 157, 159, 169, 177, 183, 187, 193, 195, 213, 219, 223, 225, 235, 237, 243, 247, 249, 253, 255, 265, 277, 285, 289, 297, 303

Offset: 1

Author

Giovanni Teofilatto, Dec 08 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, A087915.

Programs

Mathematica

tn7Q[n_]:=Module[{c=2n-7},PrimeQ[c]&&Divisible[c-3,4]]; Select[Range[ 5,301,2],tn7Q] (* Harvey P. Dale, May 18 2021 *)

Formula

a(n) = A087915(n) + 5.

Extensions

Offset corrected by Arkadiusz Wesolowski, Aug 09 2011

Corrected and extended by Harvey P. Dale, May 18 2021