A007639 Primes of form 2n^2 - 2n + 19.

19, 23, 31, 43, 59, 79, 103, 131, 163, 199, 239, 283, 331, 383, 439, 499, 563, 631, 859, 1031, 1123, 1319, 1423, 1531, 1759, 1879, 2003, 2131, 2399, 2539, 2683, 3299, 3463, 3631, 3803, 4159, 4723, 4919, 5119, 5323, 5531, 5743, 6863, 7583, 8599

Offset: 1

Author

N. J. A. Sloane, Mira Bernstein, Robert G. Wilson v

Keywords

• nonn
• easy

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• H. Dubner, Generalized Cullen numbers, J. Rec. Math., 21 (No. 3, 1989), 190-191. (Annotated scanned copy)

Crossrefs

Cf. A139827.

Programs

Magma

[a: n in [1..60] | IsPrime(a) where a is 2*n^2-2*n+19]; // Vincenzo Librandi, Mar 20 2013

Mathematica

Select[Table[2n^2-2n+19,{n,90}],PrimeQ] (* Harvey P. Dale, Dec 19 2011 *)

Formula

The primes are congruent to {2, 15, 19, 23, 31, 35, 39, 43, 51, 55, 59, 79, 87, 91, 103, 119, 131, 135, 143} (mod 148). - T. D. Noe, May 02 2008