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A020679 Numbers of form 3*x^2 + 7*y^2. 0

%I

%S 0,3,7,10,12,19,27,28,31,34,40,48,55,63,66,75,76,82,90,103,108,111,

%T 112,115,124,136,138,139,147,154,160,171,175,178,187,192,199,202,210,

%U 220,223,243,250,252,255,259,264,271,279,283,300,304,306,307,322,327,328,343,346

%N Numbers of form 3*x^2 + 7*y^2.

%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 With[{upto=350},Select[Union[3#[[1]]^2+7#[[2]]^2&/@Tuples[Range[ 0, Floor[(Sqrt[upto/3])]],2]],#<+upto&]] (* _Harvey P. Dale_, Nov 17 2012 *)

%K easy,nonn

%O 1,2

%A _David W. Wilson_

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Last modified September 25 07:27 EDT 2021. Contains 347654 sequences. (Running on oeis4.)