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A184636
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floor(1/{(n^4+2*n)^(1/4)}), where {}=fractional part.
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1
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3, 8, 18, 32, 50, 72, 98, 128, 162, 200, 242, 288, 338, 392, 450, 512, 578, 648, 722, 800, 882, 968, 1058, 1152, 1250, 1352, 1458, 1568, 1682, 1800, 1922, 2048, 2178, 2312, 2450, 2592, 2738, 2888, 3042, 3200, 3362, 3528, 3698, 3872, 4050, 4232, 4418, 4608, 4802, 5000, 5202, 5408, 5618, 5832, 6050, 6272, 6498, 6728, 6962, 7200, 7442, 7688, 7938, 8192, 8450, 8712, 8978, 9248, 9522, 9800
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OFFSET
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1,1
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COMMENTS
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Is a(n) = A001105(n) for n>=2 ?
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LINKS
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Table of n, a(n) for n=1..70.
Index entries for linear recurrences with constant coefficients, signature (3, -3, 1).
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FORMULA
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a(n)=floor(1/{(n^4+2*n)^(1/4)}), where {}=fractional part.
It appears that a(n)=3a(n-1)-3a(n-2)+a(n-3) for n>=5, and that a(n)=2*n^2 for n>=2.
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MATHEMATICA
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p[n_]:=FractionalPart[(n^4+2*n)^(1/4)];
q[n_]:=Floor[1/p[n]];
Table[q[n], {n, 1, 80}]
FindLinearRecurrence[Table[q[n], {n, 1, 1000}]]
Join[{3}, LinearRecurrence[{3, -3, 1}, {8, 18, 32}, 69]] (* Ray Chandler, Aug 02 2015 *)
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CROSSREFS
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Cf. A184536, A184635, A184637.
Sequence in context: A004210 A247022 A119881 * A075342 A083726 A319006
Adjacent sequences: A184633 A184634 A184635 * A184637 A184638 A184639
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling, Jan 18 2011
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STATUS
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approved
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