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 A140616 Primes of the form 5x^2+4xy+68y^2. 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 (list; graph; refs; listen; history; text; internal format)
 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

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Last modified May 16 11:20 EDT 2021. Contains 343942 sequences. (Running on oeis4.)