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A225824 The number of increasing rooted identity trees. 0
1, 1, 1, 4, 8, 38, 206, 1200, 7034, 53012, 465190, 4072948, 40967916, 438348328, 5113450320, 63135973560, 835727519000, 11736948927176, 175225673352928 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Unlabeled rooted identity trees are counted by A004111.  An increasing tree is a labeled tree such that any path from the root to each node is increasing.

The first 8 terms are A032301(1..8).  The 9th term is A032301(9) plus the 210 increasing labelings of the tree shown in the example.

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

There are 210 increasing labelings for this identity tree:

..........0............

........./ \...........

........0   0..........

......./   / \.........

......0   0   0........

...../    |     .......

....0     0     .......

.../            .......

..0             .......

CROSSREFS

Cf. A032305.

Sequence in context: A208820 A032301 A032213 * A032317 A032226 A001889

Adjacent sequences:  A225821 A225822 A225823 * A225825 A225826 A225827

KEYWORD

nonn,more

AUTHOR

Geoffrey Critzer, Jul 30 2013

EXTENSIONS

a(12)-a(19) from Alois P. Heinz, Aug 02 2013

STATUS

approved

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Last modified December 7 09:33 EST 2019. Contains 329843 sequences. (Running on oeis4.)