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A038055
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Number of n-node rooted trees with nodes of 2 colors.
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10
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2, 4, 14, 52, 214, 916, 4116, 18996, 89894, 433196, 2119904, 10503612, 52594476, 265713532, 1352796790, 6933598208, 35747017596, 185260197772, 964585369012, 5043220350012, 26467146038744, 139375369621960, 736229024863276, 3900074570513316, 20714056652990194
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..25.
Index entries for sequences related to rooted trees
N. J. A. Sloane, Transforms
Index entries for sequences related to trees
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FORMULA
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Shifts left and halves under Euler transform. A000151*2.
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MAPLE
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spec := [N, {N=Prod(bead, Set(N)), bead=Union(R, B), R=Atom, B=Atom}]; [seq(combstruct[count](spec, size=n), n=1..40)];
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CROSSREFS
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Cf. A000081, A038056-A038062.
Sequence in context: A055727 A003500 A129876 * A006385 A183949 A131180
Adjacent sequences: A038052 A038053 A038054 * A038056 A038057 A038058
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KEYWORD
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nonn,eigen,nice,changed
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AUTHOR
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Christian G. Bower, Jan 04 1999.
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STATUS
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approved
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