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 A139992 Primes of the form 20x^2+20xy+47y^2. 2
 47, 167, 383, 503, 647, 887, 983, 1223, 1487, 1823, 1847, 2063, 2663, 2687, 2903, 3023, 3167, 3407, 3527, 3863, 4007, 4583, 4703, 5087, 5927, 6047, 6263, 6863, 7103, 7607, 7703, 7727, 8447, 8543, 8783, 9623, 9743, 9887, 10223, 10247, 10463 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Discriminant=-3360. See A139827 for more information. Also primes of the forms 47x^2+40xy+80y^2 and 47x^2+42xy+63y^2. See A140633. - T. D. Noe, May 19 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) FORMULA The primes are congruent to {47, 143, 167, 383, 503, 647} (mod 840). MATHEMATICA QuadPrimes2[20, -20, 47, 10000] (* see A106856 *) PROG (Magma) [p: p in PrimesUpTo(12000) | p mod 840 in [47, 143, 167, 383, 503, 647]]; // Vincenzo Librandi, Aug 03 2012 CROSSREFS Sequence in context: A132251 A078857 A216827 * A142916 A253351 A253344 Adjacent sequences: A139989 A139990 A139991 * A139993 A139994 A139995 KEYWORD nonn,easy AUTHOR T. D. Noe, May 02 2008 STATUS approved

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Last modified February 6 14:32 EST 2023. Contains 360110 sequences. (Running on oeis4.)