A139974 - OEIS

A139974

Primes of the form 13x^2+40y^2.

13, 53, 157, 173, 277, 373, 653, 677, 757, 797, 997, 1013, 1093, 1117, 1213, 1277, 1453, 1613, 1637, 1693, 1733, 1933, 1973, 2053, 2213, 2237, 2357, 2557, 2677, 2837, 3253, 3533, 3613, 3637, 3797, 3877, 3917, 4013, 4133, 4157, 4397, 4637

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OFFSET

1,1

COMMENTS

Discriminant=-2080. See A139827 for more information.

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)

FORMULA

Except for 13, the primes are congruent to {53, 77, 133, 157, 173, 237, 277, 373, 413, 477, 493, 517} (mod 520).

MATHEMATICA

QuadPrimes2[13, 0, 40, 10000] (* see A106856 *)

PROG

(Magma) [13] cat [p: p in PrimesUpTo(6000) | p mod 520 in [53, 77, 133, 157, 173, 237, 277, 373, 413, 477, 493, 517]]; // Vincenzo Librandi, Aug 03 2012

CROSSREFS

Sequence in context: A041322 A022284 A179549 * A142188 A248409 A206444

Adjacent sequences: A139971 A139972 A139973 * A139975 A139976 A139977

KEYWORD

nonn,easy

AUTHOR

T. D. Noe, May 02 2008

STATUS

approved