A002970 Numbers k such that 4*k^2 + 9 is prime. (Formerly M3248)

1, 4, 5, 10, 16, 19, 20, 26, 29, 31, 35, 41, 44, 49, 50, 55, 56, 59, 70, 71, 80, 85, 94, 95, 100, 101, 106, 109, 110, 121, 149, 154, 160, 166, 175, 179, 184, 190, 191, 200, 205, 206, 211, 224, 236, 241, 245, 251, 256, 265, 269, 271, 284, 286, 289, 299, 304, 314

Offset

1,2

References

E. Kogbetliantz and A. Krikorian, Handbook of First Complex Prime Numbers, Gordon and Breach, NY, 1971, p. 1.

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

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

E. Kogbetliantz and A. Krikorian Handbook of First Complex Prime Numbers, Gordon and Breach, NY, 1971. [Annotated scans of a few pages]

Mathematica

Select[Range[350], PrimeQ[4 #^2 + 9] &] (* Vincenzo Librandi, Mar 19 2014 *)

Prog

(Magma)[n: n in [0..600]|IsPrime(4*n^2+9)]; // Vincenzo Librandi, Nov 21 2010
(PARI) is(n)=isprime(4*n^2+9) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Sequence in context: A354968 A102006 A118735 * A073611 A058594 A285289

Adjacent sequences: A002967 A002968 A002969 * A002971 A002972 A002973

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved