

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
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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



