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A056874 Primes of form (x^2+11*y^2)/4. 3
3, 5, 11, 23, 31, 37, 47, 53, 59, 67, 71, 89, 97, 103, 113, 137, 157, 163, 179, 181, 191, 199, 223, 229, 251, 257, 269, 311, 313, 317, 331, 353, 367, 379, 383, 389, 397, 401, 419, 421, 433, 443, 449, 463, 467, 487, 499, 509, 521, 577, 587, 599 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Also primes of the form x^2-xy+3y^2 with x and y nonnegative. - T. D. Noe (noe(AT)sspectra.com), May 07 2005

MAPLE

a := []; for x from 0 to 80 do for y from 1 to 26 do p := (x^2+11*y^2)/4; if whattype(p) = integer then if isprime(p) then a := [op(a), [p, x, y]]; fi; fi; od: od: writeto(trans); for i from 1 to 158 do lprint(a[i]); od: # then sort the list in "trans"

MATHEMATICA

QuadPrimes[1, -1, 3, 10000] (* see A106856 *)

CROSSREFS

Cf. A002346 and A002347 for values of x and y.

Sequence in context: A023202 A049436 A117010 * A109927 A146276 A155753

Adjacent sequences:  A056871 A056872 A056873 * A056875 A056876 A056877

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Sep 02 2000

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.