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 A140620 Primes of the form 23x^2+4xy+68y^2. 2

%I

%S 23,263,503,647,887,1223,1583,1823,1847,2063,2207,2447,2687,2903,3407,

%T 3527,3623,3767,4007,4463,4703,4943,4967,5087,5303,5807,5903,5927,

%U 6263,6863,7127,7487,7583,7823,8087,8423,8447,9623,9767,10007,10247

%N Primes of the form 23x^2+4xy+68y^2.

%C Discriminant=-6240. Also primes of the form 23x^2+18xy+207y^2.

%C In base 12, the sequence is 1E, 19E, 35E, 45E, 61E, 85E, XEE, 107E, 109E, 123E, 133E, 14EE, 167E, 181E, 1E7E, 205E, 211E, 221E, 239E, 26EE, 287E, 2X3E, 2X5E, 2E3E, 309E, 343E, 34EE, 351E, 375E, 3E7E, 415E, 43EE, 447E, 463E, 481E, 4X5E, 4X7E, 569E, 579E, 595E, 5E1E, where X is 10 and E is 11. Moreover, the discriminant is -3740. - _Walter Kehowski_, Jun 01 2008

%H Vincenzo Librandi and Ray Chandler, <a href="/A140620/b140620.txt">Table of n, a(n) for n = 1..10000</a> [First 1000 terms from Vincenzo Librandi]

%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)

%t Union[QuadPrimes2[23, 4, 68, 10000], QuadPrimes2[23, -4, 68, 10000]] (* see A106856 *)

%Y Cf. A140633.

%K nonn,easy

%O 1,1

%A _T. D. Noe_, May 19 2008

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Last modified July 27 10:44 EDT 2021. Contains 346304 sequences. (Running on oeis4.)