login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A139666
Primes of the form x^2 + 1320*y^2.
2
1321, 1489, 1609, 2161, 2281, 2689, 3001, 3169, 3529, 4129, 4801, 5281, 5449, 5569, 5641, 6121, 6361, 6961, 7129, 7489, 7561, 7681, 8089, 8209, 8761, 9001, 9241, 9601, 9769, 10321, 10729, 12049, 12241, 12409, 12721, 12841, 13249, 13729
OFFSET
1,1
COMMENTS
Discriminant = -5280. See A139643 for more information.
The primes are congruent to {1, 49, 169, 289, 361, 529, 841, 889, 961, 1081} (mod 1320).
LINKS
Vincenzo Librandi and Ray Chandler, Table of n, a(n) for n = 1..10000 (first 1000 terms from Vincenzo Librandi).
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
MATHEMATICA
QuadPrimes2[1, 0, 1320, 10000] (* see A106856 *)
PROG
(Magma) [ p: p in PrimesUpTo(15000) | p mod 1320 in {1, 49, 169, 289, 361, 529, 841, 889, 961, 1081}]; // Vincenzo Librandi, Jul 29 2012
(Magma) k:=1320; [p: p in PrimesUpTo(14000) | NormEquation(k, p) eq true]; // Bruno Berselli, Jun 01 2016
CROSSREFS
Sequence in context: A295449 A092088 A068302 * A186469 A145754 A020403
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, Apr 29 2008
STATUS
approved