A139916 - OEIS

A139916

Primes of the form 7x^2+40y^2.

7, 47, 103, 167, 223, 367, 383, 503, 607, 647, 727, 887, 983, 1063, 1223, 1447, 1487, 1543, 1567, 1783, 1823, 1847, 2063, 2287, 2383, 2663, 2687, 2887, 2903, 3023, 3167, 3407, 3463, 3527, 3583, 3727, 3863, 3967, 4007, 4423, 4567, 4583, 4703

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Discriminant=-1120. See A139827 for more information.

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)

FORMULA

Except for 7, the primes are congruent to {47, 87, 103, 143, 167, 223} (mod 280).

MATHEMATICA

QuadPrimes2[7, 0, 40, 10000] (* see A106856 *)

PROG

(Magma) [7] cat [ p: p in PrimesUpTo(6000) | p mod 280 in [47, 87, 103, 143, 167, 223]]; // Vincenzo Librandi, Aug 01 2012

CROSSREFS

Sequence in context: A261183 A067658 A044490 * A376246 A009219 A348394

Adjacent sequences: A139913 A139914 A139915 * A139917 A139918 A139919

KEYWORD

nonn,easy

AUTHOR

T. D. Noe, May 02 2008

STATUS

approved