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Number of different numbers <= n that are sums of 3 positive cubes.
0

%I #9 Sep 14 2020 15:23:03

%S 0,0,1,1,1,1,1,1,1,2,2,2,2,2,2,2,3,3,3,3,3,3,3,4,4,4,4,4,5,5,5,5,5,5,

%T 5,6,6,6,6,6,6,6,7,7,7,7,7,7,7,7,7,7,7,7,8,8,8,8,8,8,8,9,9,9,9,10,10,

%U 10,10,10,10,10,11,11,11,11,11,11,11,12,13,13,13,13,13,13,13,13,13,13,13,14,14

%N Number of different numbers <= n that are sums of 3 positive cubes.

%D H. Davenport, Sums of three positive cubes, J. London Math. Soc., 25 (1950), 339-343. Coll. Works III p. 999.

%t Accumulate[Table[If[Length[Select[PowersRepresentations[n,3,3],FreeQ[ #,0]&]]>0,1,0],{n,100}]] (* _Harvey P. Dale_, Sep 14 2020 *)

%Y Cf. A003072.

%K nonn

%O 1,10

%A _N. J. A. Sloane_, _David W. Wilson_