OFFSET
1,1
COMMENTS
Discriminant=-448. See A139827 for more information.
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
Except for 7, the primes are congruent to {15, 23, 39} (mod 56).
MATHEMATICA
QuadPrimes2[7, 0, 16, 10000] (* see A106856 *)
PROG
(Magma) [7] cat [ p: p in PrimesUpTo(3000) | p mod 56 in {15, 23, 39}]; // Vincenzo Librandi, Jul 29 2012
(PARI) list(lim)=my(v=List(), w, t); for(x=1, sqrtint(lim\7), w=7*x^2; for(y=0, sqrtint((lim-w)\16), if(isprime(t=w+16*y^2), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Feb 22 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, May 02 2008
STATUS
approved