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Search: id:A038059
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| A038059 |
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Number of rooted trees with 3-colored nodes. |
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+0
3
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| 3, 9, 45, 246, 1485, 9432, 62625, 428319, 3000393, 21410436, 155106693, 1137703869, 8432624850, 63060142671, 475196487363, 3604851603690, 27507181503069, 210988219961637, 1625848092941463, 12580709718788622
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Index entries for sequences related to rooted trees
Index entries for sequences related to trees
N. J. A. Sloane, Transforms
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FORMULA
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Shifts left and divides by 3 under Euler transform. A006964*3.
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MAPLE
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with (numtheory): a:= proc(n) option remember; local d, j; if n<=1 then 3*n else (add (d*a(d)*3, d=divisors(n-1)) +add (add (d*a(d), d=divisors(j)) *a(n-j), j=1..n-2))/ (n-1) fi end: seq (a(n), n=1..20); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 06 2008]
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CROSSREFS
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Cf. A000081, A038055-A038062.
Sequence in context: A000246 A103620 A138315 this_sequence A004990 A027616 A013492
Adjacent sequences: A038056 A038057 A038058 this_sequence A038060 A038061 A038062
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KEYWORD
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nonn,eigen
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Jan 04 1999.
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