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Search: id:A119852
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| A119852 |
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Number of ternary words with exactly one 012. |
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+0
2
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| 0, 0, 0, 1, 6, 27, 106, 387, 1350, 4566, 15102, 49113, 157622, 500520, 1575558, 4923536, 15290784, 47235771, 145246224, 444814533, 1357368786, 4128880561, 12523521786, 37888119522, 114358226428, 344437708131, 1035409733820
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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Except for the initial three zeros, convolution of A076264 with itself. Column 1 of A119851.
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FORMULA
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G.f.=z^3/(1-3z+z^2)^2.
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EXAMPLE
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a(4)=6 because we have 0012, 0120, 0121, 0122, 1012, and 2012.
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MAPLE
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G:=z^3/(1-3*z+z^3)^2: Gser:=series(G, z=0, 34): seq(coeff(Gser, z, n), n=0..30);
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CROSSREFS
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Cf. A076264, A119851.
Adjacent sequences: A119849 A119850 A119851 this_sequence A119853 A119854 A119855
Sequence in context: A000395 A005325 A099623 this_sequence A027471 A037695 A094829
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), May 26 2006
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