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A069905
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Number of partitions of n into 3 positive parts.
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10
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0, 0, 0, 1, 1, 2, 3, 4, 5, 7, 8, 10, 12, 14, 16, 19, 21, 24, 27, 30, 33, 37, 40, 44, 48, 52, 56, 61, 65, 70, 75, 80, 85, 91, 96, 102, 108, 114, 120, 127, 133, 140, 147, 154, 161, 169, 176, 184, 192, 200, 208, 217, 225, 234, 243, 252, 261, 271, 280, 290, 300, 310, 320, 331, 341
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,6
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COMMENTS
| Number of binary bracelets of n beads, 3 of them 0. For n>=3 a(n-3) is the number of binary bracelets of n beads, 3 of them 0, with 00 prohibited. [From Washington Bomfim (webonfim(AT)bol.com.br), Aug 27 2008]
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REFERENCES
| D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.4, p. 410.
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,1,0,-1,-1,1).
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FORMULA
| G.f.: x^3/((1-x)*(1-x^2)*(1-x^3)); a(n) = nearest integer to n^2/12.
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MAPLE
| A069905 := n->round(n^2/12);
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CROSSREFS
| Another version of A001399, which is the main entry for this sequence.
Sequence in context: A034163 A034092 A001399 * A008761 A008760 A008759
Adjacent sequences: A069902 A069903 A069904 * A069906 A069907 A069908
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 04 2002
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