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A141373 Primes of the form 3*x^2+16*y^2. Also primes of the form 4*x^2+4*x*y-5*y^2 (as well as primes the form 4*x^2+12*x*y+3*y^2). 9
3, 19, 43, 67, 139, 163, 211, 283, 307, 331, 379, 499, 523, 547, 571, 619, 643, 691, 739, 787, 811, 859, 883, 907, 1051, 1123, 1171, 1291, 1459, 1483, 1531, 1579, 1627, 1699, 1723, 1747, 1867, 1987, 2011, 2083, 2131, 2179, 2203, 2251, 2347, 2371, 2467, 2539 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The discriminant is -192 (or 96, or ...), depending on which quadratic form is used for the definition. Binary quadratic forms a*x^2+b*x*y+c*y^2 have discriminant d=b^2-4ac and gcd(a,b,c)=1. See A107132 for more information.

Except for 3, also primes of the forms 4x^2 + 4xy + 19y^2 and 16x^2 + 8xy + 19y^2. See A140633. - T. D. Noe, May 19 2008

REFERENCES

Z. I. Borevich and I. R. Shafarevich, Number Theory.

D. B. Zagier, Zetafunktionen und quadratische Koerper.

LINKS

Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi]

William C. Jagy and Irving Kaplansky, Positive definite binary quadratic forms that represent the same primes [Cached copy] See Table II.

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

FORMULA

Except for 3, the primes are congruent to 19 (mod 24). - T. D. Noe, May 02 2008

EXAMPLE

19 is a member because we can write 19=4*2^2+4*2*1-5*1^2 (or 19=4*1^2+12*1*1+3*1^2).

MATHEMATICA

QuadPrimes2[3, 0, 16, 10000] (* see A106856 *)

PROG

(MAGMA) [3] cat [ p: p in PrimesUpTo(3000) | p mod 24 in {19 } ]; // Vincenzo Librandi, Jul 24 2012

(PARI) list(lim)=my(v=List(), w, t); for(x=1, sqrtint(lim\3), w=3*x^2; for(y=0, sqrtint((lim-w)\16), if(isprime(t=w+16*y^2), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017

CROSSREFS

Cf. A107132, A139827, A107003, A141375, A141376 (d=96).

See also A038872 (d=5),

A038873 (d=8),

A068228, A141123 (d=12),

A038883 (d=13),

A038889 (d=17),

A141158 (d=20),

A141159, A141160 (d=21),

A141170, A141171 (d=24),

A141172, A141173 (d=28),

A141174, A141175 (d=32),

A141176, A141177 (d=33),

A141178 (d=37),

A141179, A141180 (d=40),

A141181 (d=41),

A141182, A141183 (d=44),

A033212, A141785 (d=45),

A068228, A141187 (d=48),

A141188 (d=52),

A141189 (d=53),

A141190, A141191 (d=56),

A141192, A141193 (d=57),

A107152, A141302, A141303, A141304 (d=60),

A141215 (d=61),

A141111, A141112 (d=65),

A141336, A141337 (d=92),

A141338, A141339 (d=93),

A141161, A141163 (d=148),

A141165, A141166 (d=229),

A141167, A141167, A141167 (d=257).

Sequence in context: A141644 A141170 A107154 * A031393 A146672 A146704

Adjacent sequences:  A141370 A141371 A141372 * A141374 A141375 A141376

KEYWORD

nonn

AUTHOR

T. D. Noe, May 13 2005; Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 28 2008

EXTENSIONS

More terms from Colin Barker, Apr 05 2015

Edited by N. J. A. Sloane, Jul 14 2019, combining two identical entries both with multiple cross-references.

STATUS

approved

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Last modified February 26 18:29 EST 2020. Contains 332293 sequences. (Running on oeis4.)