OFFSET
1,1
COMMENTS
Appears to also be the primes p such that p mod 6 = 1 and Fibonacci(p) mod 6 = 1. - Gary Detlefs, May 26 2014
LINKS
N. J. A. Sloane and Vincenzo Librandi, Table of n, a(n) for n = 1..10000 (The first 2000 terms were found by Vincenzo Librandi)
David A. Cox, Primes of the Form x^2 + n y^2, Wiley, 1989, p. 36.
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
FORMULA
Same as primes congruent to 1 or 7 mod 24. See e.g. Cox, p. 36.
a(n) ~ 4n log n. - Charles R Greathouse IV, Nov 09 2012
MATHEMATICA
f[x_, y_] := x^2 + 6*y^2; lst = {}; Do[p = f[x, y]; If[ PrimeQ[ p], AppendTo[ lst, p]], {y, 20}, {x, 50}]; Take[ Union[ lst], 50] (* Vladimir Joseph Stephan Orlovsky, Aug 04 2009 *)
PROG
(PARI) select(n->n%24==1||n%24==7, primes(100)) \\ Charles R Greathouse IV, Nov 09 2012
(Magma) [p: p in PrimesUpTo(1600) | NormEquation(6, p) eq true]; // Bruno Berselli, Jul 03 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Removed defective Mma program; extended the b-file using Charles R Greathouse's PARI program. - N. J. A. Sloane, Jun 06 2014
STATUS
approved