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A130980
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G.f. : 16/(7 + 9*sqrt (1 - 32*x)).
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5
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1, 9, 153, 3177, 73017, 1785609, 45543897, 1197639081, 32231934585, 883404542025, 24570973169433, 691759954058985, 19674867844155321, 564462038150345097, 16315646312285498457, 474680922491822688297
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Number of walks of length 2n on the 9-regular tree beginning and ending at some fixed vertex. Hankel transform is A135320. [From Philippe DELEHAM, Feb 25 2009]
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FORMULA
| a(n) = Sum_{k=0..n} A039599(n,k)*8^(n-k). - Philippe DELEHAM, Aug 25 2007
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CROSSREFS
| Sequence in context: A165232 A169958 A012017 * A133309 A151835 A113391
Adjacent sequences: A130977 A130978 A130979 * A130981 A130982 A130983
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KEYWORD
| nonn
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Aug 23 2007
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EXTENSIONS
| More terms from Olivier Gerard (Sep 22 2007).
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