A096689 Numbers n such that 2n^2 + 3n + 3 is prime.

0, 2, 4, 10, 16, 20, 26, 34, 40, 44, 46, 50, 62, 64, 74, 76, 80, 82, 86, 92, 94, 110, 122, 140, 160, 164, 170, 176, 182, 200, 202, 212, 214, 220, 224, 232, 236, 250, 262, 296, 302, 304, 310, 320, 322, 326, 332, 344, 346, 352, 392, 400, 404, 422, 424, 446, 452

Offset: 1

Author

Ray Chandler, Jul 12 2004

Keywords

• nonn

Comments

All n are {2,4} (mod 6), as in A047235, because otherwise 2*n^2 + 3*n + 3 is a multiple of 2 or 3. - R. J. Mathar, Jul 17 2012

Crossrefs

Cf. A095697, A096690, A096691.

Programs

Mathematica

f[n_]:=n^2+(n+1)^2+(n+2); lst={};Do[p=f[n];If[PrimeQ[p],AppendTo[lst,n]],{n,0,6!}];lst (* Vladimir Joseph Stephan Orlovsky, Jul 04 2009 *)
Select[Range[0,500],PrimeQ[2#^2+3#+3]&] (* Harvey P. Dale, Jul 19 2011 *)

PARI

is(n)=isprime(2*n^2+3*n+3) \\ Charles R Greathouse IV, May 22 2017

Formula

a(n) = A096691(n)*2.