A107143 Primes of the form 2x^2 + 19y^2.
2, 19, 37, 173, 179, 181, 269, 307, 509, 547, 563, 683, 971, 1093, 1123, 1171, 1229, 1381, 1523, 1571, 1579, 1627, 1637, 1667, 1877, 1931, 1933, 2083, 2339, 2371, 2389, 2621, 2731, 2749, 2789, 2909, 3061, 3067, 3109, 3181, 3221, 3229, 3371
Offset: 1
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)
Programs
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Mathematica
QuadPrimes2[2, 0, 19, 10000] (* see A106856 *)
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PARI
list(lim)=my(v=List(),w,t); for(x=0, sqrtint(lim\2), w=2*x^2; for(y=0, sqrtint((lim-w)\19), if(isprime(t=w+19*y^2), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017
Comments