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A106872 Primes of the form 2x^2+xy+4y^2, with x and y any integer. 2
2, 5, 7, 19, 41, 59, 71, 97, 101, 103, 107, 109, 113, 157, 163, 191, 193, 211, 233, 257, 281, 307, 311, 317, 359, 373, 397, 419, 421, 439, 443, 467, 479, 503, 541, 547, 563, 593, 599, 659, 661, 683, 691, 701, 727, 733, 751, 769, 877, 887, 907, 977, 997, 1033 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Discriminant=-31. See A106856 for more information.

Primes p such that the polynomial x^3-x^2-1 is irreducible over Zp. The polynomial discriminant is also -31. - T. D. Noe (noe(AT)sspectra.com), May 13 2005

MATHEMATICA

f[x_, y_]:=2*x^2+x*y+4*y^2; lst={}; Do[Do[p=f[x, y]; If[PrimeQ[p], AppendTo[lst, p]], {y, -5!, 6!}], {x, -5!, 6!}]; Take[Union[lst], 5! ] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jul 04 2009]

Union[QuadPrimes[2, 1, 4, 10000], QuadPrimes[2, -1, 4, 10000]] (* see A106856 *)

CROSSREFS

Sequence in context: A046115 A089443 A191024 * A071198 A041387 A096146

Adjacent sequences:  A106869 A106870 A106871 * A106873 A106874 A106875

KEYWORD

nonn,easy

AUTHOR

T. D. Noe (noe(AT)sspectra.com), May 09 2005

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