|
|
A318850
|
|
Number of rooted trees with n nodes such that no more than three isomorphic subtrees extend from the same node.
|
|
2
|
|
|
0, 1, 1, 2, 4, 8, 18, 43, 102, 250, 623, 1579, 4042, 10473, 27356, 72049, 190991, 509384, 1365586, 3678369, 9949452, 27014550, 73600711, 201153143, 551329088, 1515078957, 4173575232, 11522620375, 31878127954, 88362886345, 245372235144, 682508792835
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,4
|
|
LINKS
|
|
|
MAPLE
|
h:= proc(n, m, t) option remember; `if`(m=0, binomial(n+t, t),
`if`(n=0, 0, add(h(n-1, m-j, t+1), j=1..min(3, m))))
end:
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1)*h(a(i), j, 0), j=0..n/i)))
end:
a:= n-> `if`(n<2, n, b(n-1$2)):
seq(a(n), n=0..35);
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|