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A139855 Primes of the form 4x^2+4xy+31y^2. 2
31, 79, 151, 199, 271, 439, 631, 751, 919, 991, 1039, 1231, 1279, 1399, 1471, 1759, 1831, 1879, 1951, 1999, 2239, 2311, 2551, 2671, 2719, 2791, 3079, 3271, 3319, 3391, 3511, 3559, 3631, 3919, 4111, 4159, 4231, 4519, 4591, 4639, 4759, 4831 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Discriminant=-480. See A139827 for more information.

Also primes of the form 15x^2+16y^2, which has discriminant=-960. - T. D. Noe (noe(AT)sspectra.com), May 07 2008

Also primes of the form 16x^2+8xy+31y^2, which has discriminant -1920. See A140633. - T. D. Noe (noe(AT)sspectra.com), May 19 2008

FORMULA

The primes are congruent to {31, 79} (mod 120).

MATHEMATICA

QuadPrimes[4, -4, 31, 10000] (* see A106856 *)

CROSSREFS

Sequence in context: A142408 A033220 * A139901 A044169 A044550 A055810

Adjacent sequences:  A139852 A139853 A139854 * A139856 A139857 A139858

KEYWORD

nonn,easy

AUTHOR

T. D. Noe (noe(AT)sspectra.com), May 02 2008

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Last modified February 16 01:31 EST 2012. Contains 205860 sequences.