%I #5 Apr 06 2015 10:45:45
%S 8,40,120,128,272,312,520,640,648,888,1160,1200,1400,1920,2040,2048,
%T 2080,2952,2968,3240,3280,4040,4352,4872,4992,5000,5368,6120,6960,
%U 7008,7280,7320,8320,8840,9720
%N Numbers of the form 4x^3y+4y x^3 (where x,y are positive integers).
%C Squares of these numbers are of the form N^4-M^2 (where N belongs to A135786 and M to A135797) Proof uses: (4x^3y+4xy^3)^2=(x^2-y^2)^4+(x^4+6x^2y^2+y^4)^2.
%C Refers to A057102, which had an incorrect description and has been replaced by A256418. As a result the present sequence should be re-checked. - _N. J. A. Sloane_, Apr 06 2015
%t a = {}; Do[Do[w = 4x^3y + 4x y^3; If[w < 10000, AppendTo[a, w]], {x, y, 1000}], {y, 1, 1000}]; Union[a] (*Artur Jasinski*)
%Y Cf. A000404, A050803, A057102, A135784, A060803, A135786, A135787, A135789, A135790, A135791, A135792, A135793, A135795, A135796, A135797.
%K nonn
%O 1,1
%A _Artur Jasinski_, Nov 29 2007