A106950 Primes of the form x^2 + 18y^2.

19, 43, 67, 73, 97, 139, 163, 193, 211, 241, 283, 307, 313, 331, 337, 379, 409, 433, 457, 499, 523, 547, 571, 577, 601, 619, 643, 673, 691, 739, 769, 787, 811, 859, 883, 907, 937, 1009, 1033, 1051, 1123, 1129, 1153, 1171, 1201, 1249, 1291, 1297, 1321

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 1,19 modulo 24. - Michael Somos, Aug 19 2006

Mathematica

QuadPrimes2[1, 0, 18, 10000] (* see A106856 *)

Prog

(PARI) {a(n)= my(m, c); if(n<1, 0, c=0; m=0; while( c<n, m++; if( isprime(m)& m%24==1||m%24==19, c++)); m)} /* Michael Somos, Aug 19 2006 */
(Magma) [ p: p in PrimesUpTo(2000) | p mod 24 in {1, 19} ]; // Vincenzo Librandi, Jul 22 2012

Crossrefs

Sequence in context: A095079 A238676 A087779 * A141438 A350051 A095103

Adjacent sequences: A106947 A106948 A106949 * A106951 A106952 A106953

Keyword

nonn,easy,changed

Author

T. D. Noe, May 09 2005

Status

approved