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A212132
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Number of (w,x,y,z) with all terms in {1,...,n} and w*x+y*z>=n^2.
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2
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0, 1, 11, 33, 76, 144, 262, 415, 655, 959, 1377, 1886, 2610, 3396, 4465, 5689, 7169, 8883, 11042, 13334, 16240, 19355, 23003, 27059, 31892, 36952, 42878, 49384, 56659, 64471, 73683, 83042, 93938, 105470, 118114, 131855, 147087, 162883
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OFFSET
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0,3
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COMMENTS
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A212132(n)+A212111(n)=n^4. For a guide to related sequences, see A211795.
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LINKS
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Table of n, a(n) for n=0..37.
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MATHEMATICA
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t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w*x + y*z >= n^2, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 40]] (* A212132 *)
(* Peter J. C. Moses, Apr 13 2012 *)
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CROSSREFS
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Cf. A211795.
Sequence in context: A080859 A063036 A163673 * A027025 A120354 A206527
Adjacent sequences: A212129 A212130 A212131 * A212133 A212134 A212135
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling, May 07 2012
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STATUS
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approved
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