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Numbers not of form x^2 + 2y^2 + 2yz + 4z^2.
2

%I #7 Mar 27 2019 20:50:08

%S 7,10,21,35,42,70,79,84,91,119,133,140,168,182,189,217,231,238,259,

%T 266,280,287,315,329,336,343,364,378,385,413,427,434,462,476,483,490,

%U 511,525,532,560,574,581,609,623,630,658,672,679,707,721,728,756,770,777

%N Numbers not of form x^2 + 2y^2 + 2yz + 4z^2.

%t t = Union[ Flatten[ Table[ x^2 + 2y^2 + 2y*z + 4z^2, {x, 0, 28}, {y, -23, 23}, {z, -16, 16}]]]; Complement[ Range[ 800], Take[t, 747]] (* _Robert G. Wilson v_, Aug 21 2004 *)

%Y Complement of A000398.

%Y Cf. A306469.

%K nonn

%O 1,1

%A _Ralf Stephan_, Aug 20 2004

%E More terms from _Robert G. Wilson v_, Aug 21 2004