[go: up one dir, main page]

login
A244706
Number of n-node unlabeled rooted trees with thinning limbs and root outdegree (branching factor) 5.
2
1, 1, 3, 6, 15, 31, 72, 153, 346, 752, 1673, 3661, 8108, 17814, 39349, 86646, 191251, 421596, 930519, 2052789, 4531648, 10002857, 22088709, 48780279, 107757048, 238069894, 526096509, 1162775782, 2570487392, 5683401236, 12568472173, 27799055016, 61496981626
OFFSET
6,3
COMMENTS
In a rooted tree with thinning limbs the outdegree of a parent node is larger than or equal to the outdegree of any of its child nodes.
LINKS
MAPLE
b:= proc(n, i, h, v) option remember; `if`(n=0,
`if`(v=0, 1, 0), `if`(i<1 or v<1 or n<v, 0,
`if`(n=v, 1, add(binomial(A(i, min(i-1, h))+j-1, j)
*b(n-i*j, i-1, h, v-j), j=0..min(n/i, v)))))
end:
A:= proc(n, k) option remember;
`if`(n<2, n, add(b(n-1$2, j$2), j=1..min(k, n-1)))
end:
a:= n-> b(n-1$2, 5$2):
seq(a(n), n=6..50);
CROSSREFS
Column k=5 of A244657.
Sequence in context: A256281 A034739 A276670 * A097941 A317792 A293732
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 04 2014
STATUS
approved