A106963 Primes of the form 4x^2 + 5y^2.

5, 41, 61, 109, 149, 241, 269, 281, 389, 409, 421, 449, 569, 601, 641, 661, 701, 821, 829, 881, 929, 1069, 1129, 1181, 1201, 1301, 1321, 1381, 1429, 1481, 1489, 1609, 1801, 1889, 1901, 1949, 2129, 2141, 2161, 2221, 2269, 2281, 2309, 2341, 2381

Offset

1,1

Comments

Discriminant = -80.

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)

Mathematica

QuadPrimes2[4, 0, 5, 10000] (* see A106856 *)

Prog

(PARI) list(lim)=my(v=List(), w, t); for(x=0, sqrtint(lim\4), w=4*x^2; for(y=1, sqrtint((lim-w)\5), if(isprime(t=w+5*y^2), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017

Crossrefs

Sequence in context: A302692 A232881 A174054 * A276916 A203018 A349786

Adjacent sequences: A106960 A106961 A106962 * A106964 A106965 A106966

Keyword

nonn,easy

Author

T. D. Noe, May 09 2005

Status

approved