A107211 Primes of the form 2x^2 + 47y^2.
2, 47, 79, 97, 431, 439, 521, 761, 769, 929, 1193, 1223, 1297, 1303, 1399, 1481, 1567, 1753, 1823, 1847, 2143, 2311, 2503, 2591, 2633, 2753, 2857, 3089, 3271, 3361, 3623, 3761, 3767, 3919, 4007, 4049, 4217, 4481, 4703, 5407, 5503, 5689
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, 47, 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)\47), if(isprime(t=w+47*y^2), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Feb 10 2017
Comments