A106924 Primes of the form 4x^2 + xy + 4y^2, with x and y any integer.

7, 37, 43, 109, 151, 193, 211, 331, 337, 379, 457, 487, 499, 673, 709, 751, 757, 883, 907, 919, 991, 1117, 1171, 1201, 1303, 1327, 1381, 1423, 1429, 1453, 1471, 1549, 1597, 1747, 1759, 1789, 1801, 1873, 2017, 2053, 2083, 2137, 2143, 2221, 2311, 2347

Offset

1,1

Comments

Discriminant = -63.

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

Union[QuadPrimes2[4, 1, 4, 10000], QuadPrimes2[4, -1, 4, 10000]] (* see A106856 *)

Prog

(PARI) {a(n)= local(m, c, x, y); if(n<1, 0, c=0; m=1; while( c<n, m++; if( kronecker(m, 7)!>=0&isprime(m), for(x=0, sqrtint(m\7), if(issquare(m-7*x^2, &y), if( y%3==0, c++); break)))); m)} /* Michael Somos, May 28 2005 */

Crossrefs

Sequence in context: A139492 A141159 A092475 * A076285 A077720 A235463

Adjacent sequences: A106921 A106922 A106923 * A106925 A106926 A106927

Keyword

nonn,easy

Author

T. D. Noe, May 09 2005

Status

approved