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A211646 Number of ordered triples (w,x,y) with all terms in {1,...,n} and w^2+x^2+y^2<3n. 2
0, 0, 1, 4, 10, 17, 20, 26, 35, 44, 54, 60, 75, 87, 96, 108, 120, 133, 145, 163, 178, 196, 202, 220, 238, 256, 278, 284, 308, 329, 347, 365, 383, 401, 428, 440, 467, 495, 504, 528, 549, 576, 594, 612, 645, 678, 690, 717, 735, 765, 790, 814, 853, 871 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

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]]   (* A211646 *)

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

CROSSREFS

Cf. A211422.

Sequence in context: A310535 A310536 A001549 * A287001 A310537 A310538

Adjacent sequences:  A211643 A211644 A211645 * A211647 A211648 A211649

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 18 2012

STATUS

approved

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Last modified July 21 06:55 EDT 2019. Contains 325192 sequences. (Running on oeis4.)