%I #8 Jun 20 2014 15:00:22

%S 0,3,5,7,12,13,17,20,27,28,33,45,47,48,52,55,63,68,73,75,77,80,83,87,

%T 97,103,105,108,112,117,125,132,143,145,147,153,157,167,173,175,180,

%U 187,188,192,195,203,208,213,220,223,227,237,243,245,252,255,257,272,273,283,292,293,297,300,307,308,313,320,325,327,332,343,348,353,355,357,363,367

%N Numbers of the form 3x^2+xy+3y^2.

%C Discriminant -35.

%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)

%t ofTheFormQ[n_] := Reduce[n == 3*x^2 + x*y + 3*y^2, {x, y}, Integers] =!= False; Select[Range[0, 400], ofTheFormQ] (* _Jean-François Alcover_, Jun 04 2014 *)

%Y Primes: A106878.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Jun 02 2014