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A008130
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Floor(n/3)*ceil(n/3).
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1
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0, 0, 0, 1, 2, 2, 4, 6, 6, 9, 12, 12, 16, 20, 20, 25, 30, 30, 36, 42, 42, 49, 56, 56, 64, 72, 72, 81, 90, 90, 100, 110, 110, 121, 132, 132, 144, 156, 156, 169, 182, 182, 196, 210, 210, 225, 240, 240, 256, 272, 272, 289
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,0,2,-2,0,-1,1)
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FORMULA
| a(n) = A002264(n)*A002264(n+2). G.f. -x^3*(1+x) / ( (1+x+x^2)^2*(x-1)^3 ). - R. J. Mathar, Jan 27 2011
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MATHEMATICA
| f[n_]:=Ceiling[n/3]*Floor[n/3]; Table[f[n], {n, 0, 5!}] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 01 2010]
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CROSSREFS
| Sequence in context: A039731 A005341 A137268 * A055388 A065457 A000784
Adjacent sequences: A008127 A008128 A008129 * A008131 A008132 A008133
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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