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A102273 Primes p such that Q(sqrt(-21p)) has genus characters chi_{-3} = -1, chi_{-7} = +1. 8
11, 23, 71, 107, 179, 191, 239, 263, 347, 359, 431, 443, 491, 599, 659, 683, 743, 827, 863, 911, 947, 1019, 1031, 1103, 1163, 1187, 1283, 1367, 1439, 1451, 1499, 1523, 1583, 1607, 1619, 1667, 1787, 1871, 2003, 2027, 2039, 2087 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The 2-class number of these fields is always 4.
Primes of the form 2x^2 - 2xy + 11y^2 with x nonnegative and y positive. - T. D. Noe, May 08 2005
Also primes of the forms 8x^2 + 4xy + 11y^2 and 11x^2 + 2xy + 23y^2. See A140633. - T. D. Noe, May 19 2008
The discriminant of positive definite binary quadratic form (2,2,11) is -84. - Hugo Pfoertner, Jul 14 2019
LINKS
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
FORMULA
The primes are congruent to {2, 11, 23, 71} (mod 84). - T. D. Noe, May 02 2008
MATHEMATICA
f[x_, y_]:=2*x^2+2*x*y+11*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! ] (* Vladimir Joseph Stephan Orlovsky, Jul 06 2009 *)
PROG
(Magma) [p: p in PrimesUpTo(3000) | p mod 84 in [2, 11, 23, 71]]; // Vincenzo Librandi, Jul 19 2012
CROSSREFS
Cf. A139827.
Sequence in context: A139905 A267437 A267438 * A195463 A104066 A184394
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 19 2005
STATUS
approved

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Last modified August 29 09:16 EDT 2024. Contains 375511 sequences. (Running on oeis4.)