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A029718 Numbers of form 2x^2 + 2xy + 3y^2. 2


%S 0,2,3,7,8,10,12,15,18,23,27,28,32,35,40,42,43,47,48,50,58,60,63,67,

%T 72,75,82,83,87,90,92,98,103,107,108,112,115,122,123,127,128,135,138,

%U 140,147,160,162,163,167,168,172,175,178,183,188,192,200,202,203,207,210

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

%C Numbers represented by quadratic form with Gram matrix [ 2, 1; 1, 3 ].

%D H. Cohn, A second course in number theory, John Wiley & Sons, Inc., New York-London, 1962. see page 3.

%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)

%F List contains 0 and all positive n such that 2*A035170(n) = A028586(n) is nonzero. - _Michael Somos_, Oct 21 2006

%Y Cf. A028927.

%Y For primes see A106865.

%Y For the properly represented numbers see A344232.

%K nonn

%O 1,2

%A _N. J. A. Sloane_

%E More terms from Larry Reeves (larryr(AT)acm.org), Mar 29 2000

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Last modified August 2 01:19 EDT 2021. Contains 346408 sequences. (Running on oeis4.)