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A211787 Number of (w,x,y,z) with all terms in {1,...,n} and w*x<=2*y*z. 3
0, 1, 15, 66, 201, 469, 958, 1735, 2937, 4656, 7050, 10242, 14461, 19813, 26569, 34904, 45086, 57293, 71898, 89050, 109201, 132534, 159424, 190167, 225296, 264966, 309685, 359823, 415889, 478142, 547302, 623514, 707593, 799821 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n)+A211797(n)=n^4.

See A211795 for a guide to related sequences.

LINKS

Bo Gyu Jeong, Table of n, a(n) for n = 0..200

MATHEMATICA

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

    (Do[If[w*x <= 2 y*z, s = s + 1],

    {w, 1, #}, {x, 1, #}, {y, 1, #},

      {z, 1, #}] &[n]; s)]];

Map[t[#] &, Range[0, 40]] (* A211787 *)

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

CROSSREFS

Cf. A211795.

Sequence in context: A033653 A088058 A062392 * A265141 A336624 A211917

Adjacent sequences:  A211784 A211785 A211786 * A211788 A211789 A211790

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 27 2012

STATUS

approved

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Last modified April 15 23:51 EDT 2021. Contains 343018 sequences. (Running on oeis4.)