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A211647 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2<=3n. 2
0, 1, 4, 7, 11, 17, 23, 32, 38, 48, 60, 66, 78, 87, 102, 114, 121, 139, 157, 169, 178, 196, 214, 232, 241, 263, 284, 296, 314, 329, 359, 371, 386, 410, 434, 452, 471, 495, 516, 540, 555, 582, 612, 630, 651, 678, 702, 729, 738, 772, 805, 829, 853, 871 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

For a guide to related sequences, see A211422.

LINKS

Table of n, a(n) for n=0..53.

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, 80]]  (* A211647 *)

(* Peter J. C. Moses, Apr 13 2012 *)

CROSSREFS

Cf. A211422.

Sequence in context: A126618 A171452 A049648 * A133257 A156039 A310767

Adjacent sequences:  A211644 A211645 A211646 * A211648 A211649 A211650

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 18 2012

STATUS

approved

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Last modified December 4 11:28 EST 2021. Contains 349486 sequences. (Running on oeis4.)