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 A140615 Primes of the form 13x^2+6xy+21y^2. 2
 13, 61, 109, 277, 349, 373, 541, 613, 733, 853, 877, 997, 1069, 1117, 1381, 1429, 1597, 1669, 1693, 1789, 1861, 1933, 2053, 2221, 2389, 2437, 2749, 2917, 3109, 3181, 3229, 3253, 3373, 3517, 3541, 3637, 3709, 4021, 4549, 4597, 4813, 4861 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Discriminant=-1056. Also primes of the form 13x^2+2xy+61y^2. In base 12, the sequence is 11, 51, 91, 1E1, 251, 271, 391, 431, 511, 5E1, 611, 6E1, 751, 791, 971, 9E1, E11, E71, E91, 1051, 10E1, 1151, 1231, 1351, 1471, 14E1, 1711, 1831, 1971, 1X11, 1X51, 1X71, 1E51, 2051, 2071, 2131, 2191, 23E1, 2771, 27E1, 2951, 2991, where X is 10 and E is 11. Moreover, the discriminant is -740. - 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[13, 6, 21, 10000], QuadPrimes2[13, -6, 21, 10000]] (* see A106856 *) CROSSREFS Cf. A140633. Sequence in context: A028874 A087106 A142402 * A086361 A119151 A081589 Adjacent sequences: A140612 A140613 A140614 * A140616 A140617 A140618 KEYWORD nonn,easy AUTHOR T. D. Noe, May 19 2008 STATUS approved

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Last modified March 20 20:37 EDT 2023. Contains 361391 sequences. (Running on oeis4.)