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Numbers that are not the sum of 3 nonzero squares and a positive cube.
0

%I #5 Jul 08 2020 20:45:37

%S 0,1,2,3,5,6,8,9,16,21,24,40

%N Numbers that are not the sum of 3 nonzero squares and a positive cube.

%C No more terms up to 6*10^5.

%t n = 5 * 10^4.;

%t t = Union@Flatten@Table[x^2 + y^2 + z^2 + w^3, {x,(n/3)^(1/2)}, {y,x,((n-x^2)/2)^(1/2)},{z,y,(n-x^2-y^2)^(1/2)}, {w,(n-x^2-y^2-z^2)^(1/3)}];

%t Complement[Range[0,n],t]

%Y Cf. A000534, A004214, A297788.

%K nonn,more

%O 1,3

%A _XU Pingya_, Jun 17 2020