A140616 - OEIS

A140616

Primes of the form 5x^2+4xy+68y^2.

5, 101, 173, 269, 293, 461, 509, 677, 773, 797, 941, 1013, 1109, 1181, 1277, 1301, 1613, 1637, 1949, 1973, 2141, 2309, 2357, 2477, 2621, 2693, 2789, 2861, 2957, 3461, 3533, 3701, 3797, 3821, 3989, 4133, 4157, 4373, 4493, 4637, 4877, 4973

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OFFSET

1,1

COMMENTS

Discriminant=-1344. Also primes of the form 5x^2+2xy+101y^2.

In base 12, the sequence is 5, 85, 125, 1X5, 205, 325, 365, 485, 545, 565, 665, 705, 785, 825, 8X5, 905, E25, E45, 1165, 1185, 12X5, 1405, 1445, 1525, 1625, 1685, 1745, 17X5, 1865, 2005, 2065, 2185, 2245, 2265, 2385, 2485, 24X5, 2645, 2725, 2825, 29X5, 2X65, where X is for 10 and E is for 11. Moreover, the discriminant is -940. - Walter Kehowski, May 31 2008

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

Union[QuadPrimes2[5, 4, 68, 10000], QuadPrimes2[5, -4, 68, 10000]] (* see A106856 *)

CROSSREFS

Cf. A140633.

Sequence in context: A336427 A197200 A090436 * A087456 A081220 A210362

Adjacent sequences: A140613 A140614 A140615 * A140617 A140618 A140619

KEYWORD

nonn,easy

AUTHOR

T. D. Noe, May 19 2008

STATUS

approved