A106949 Primes of the form 2x^2 + 9y^2.

2, 11, 17, 41, 59, 83, 89, 107, 113, 131, 137, 179, 227, 233, 251, 257, 281, 347, 353, 401, 419, 443, 449, 467, 491, 521, 563, 569, 587, 593, 617, 641, 659, 683, 761, 809, 827, 857, 881, 929, 947, 953, 971, 977, 1019, 1049, 1091, 1097, 1163, 1187, 1193

Offset

1,1

Comments

Discriminant = -72.

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

Primes congruent to 2,11,17 modulo 24. - Michael Somos, Aug 19 2006

Mathematica

QuadPrimes2[2, 0, 9, 10000] (* see A106856 *)

Prog

(PARI) {a(n)= local(m, c); if(n<1, 0, c=0; m=0; while( c<n, m++; if( isprime(m)& m==2|m%24==11|m%24==17, c++)); m)} /* Michael Somos, Aug 19 2006 */
(PARI) list(lim)=my(v=List([2]), t); forprime(p=11, lim, t=p%24; if(t==11||t==17, listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017
(Magma) [ p: p in PrimesUpTo(2000) | p mod 24 in {2, 11, 17} ]; // Vincenzo Librandi, Jul 22 2012

Crossrefs

Sequence in context: A252657 A296053 A234647 * A236687 A187762 A217306

Adjacent sequences: A106946 A106947 A106948 * A106950 A106951 A106952

Keyword

nonn,easy

Author

T. D. Noe, May 09 2005

Status

approved