A211648 - OEIS

A211648

Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2=3n.

0, 1, 3, 3, 1, 0, 3, 6, 3, 4, 6, 6, 3, 0, 6, 6, 1, 6, 12, 6, 0, 0, 12, 12, 3, 7, 6, 12, 6, 0, 12, 6, 3, 9, 6, 12, 4, 0, 12, 12, 6, 6, 18, 18, 6, 0, 12, 12, 3, 7, 15, 15, 0, 0, 12, 12, 6, 15, 18, 6, 6, 0, 18, 24, 1, 12, 15, 18, 6, 0, 12, 12, 12, 12, 18, 15, 6, 0, 24, 18, 0, 13, 18

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OFFSET

0,3

COMMENTS

For a guide to related sequences, see A211422.

LINKS

Table of n, a(n) for n=0..82.

MATHEMATICA

t = Compile[{{n, _Integer}}, Module[{s = 0},

(Do[If[w^2 + x^2 + y^2 == 3 n, s = s + 1],

{w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]];

Map[t[#] &, Range[0, 100]] (* A211648 *)