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A246566
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Number of rooted ordered trees with n non-root nodes such that the branch lengths are weakly decreasing.
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2
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1, 1, 2, 4, 10, 24, 62, 155, 396, 992, 2504, 6228, 15512, 38220, 94059, 229498, 558642, 1350384, 3255138, 7801327, 18642118, 44329833, 105111283, 248184255, 584396849, 1371048495, 3208318247, 7483522231, 17413665881, 40405120865, 93543352492
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OFFSET
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0,3
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LINKS
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EXAMPLE
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The a(3) = 4 such trees are:
:
: 1:
: [ 1 1 1 ]
: [ 0 0 0 ]
:
: O--o
: .--o
: .--o
:
:
: 2:
: [ 2 1 ]
: [ 0 0 ]
:
: O--o--o
: .--o
:
:
: 3:
: [ 2 1 ]
: [ 0 1 ]
:
: O--o--o
: .--o
:
:
: 4:
: [ 3 ]
: [ 0 ]
:
: O--o--o--o
:
See the Arndt link for all trees for 0 <= n <= 5.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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