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A106969 Primes of the form x^2+xy+21y^2, with x and y nonnegative. 1
23, 41, 131, 193, 199, 227, 229, 277, 293, 397, 401, 557, 607, 659, 701, 739, 773, 787, 811, 983, 1013, 1061, 1117, 1231, 1289, 1409, 1423, 1427, 1447, 1511, 1523, 1531, 1553, 1667, 1669, 1709, 1723, 1747, 1753, 1847, 1913, 1987, 1993, 2111 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Discriminant=-83.

LINKS

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

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

MATHEMATICA

QuadPrimes2[1, 1, 21, 10000] (* see A106856 *)

CROSSREFS

Sequence in context: A106970 A155702 A114379 * A304390 A309533 A306085

Adjacent sequences:  A106966 A106967 A106968 * A106970 A106971 A106972

KEYWORD

nonn,easy

AUTHOR

T. D. Noe, May 09 2005

STATUS

approved

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Last modified October 18 04:57 EDT 2019. Contains 328145 sequences. (Running on oeis4.)