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Search: id:A119826
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| A119826 |
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Number of ternary words of length n with no 000's. |
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+0
3
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| 1, 3, 9, 26, 76, 222, 648, 1892, 5524, 16128, 47088, 137480, 401392, 1171920, 3421584, 9989792, 29166592, 85155936, 248624640, 725894336, 2119349824, 6187737600, 18065963520, 52746101888, 153999606016, 449623342848
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OFFSET
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0,2
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COMMENT
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Column 0 of A119825.
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FORMULA
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G.f.=(1+z+z^2)/(1-2z-2z^2-2z^3).
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EXAMPLE
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a(4)=76 because among the 3^4=81 ternary words of length 4 only 0000, 0001, 0002, 1000 and 2000 contain 000's.
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MAPLE
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g:=(1+z+z^2)/(1-2*z-2*z^2-2*z^3): gser:=series(g, z=0, 32): seq(coeff(gser, z, n), n=0..28);
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CROSSREFS
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Cf. A119825, A119827.
Sequence in context: A018919 A005774 A101169 this_sequence A027915 A114982 A133405
Adjacent sequences: A119823 A119824 A119825 this_sequence A119827 A119828 A119829
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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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