login
A245124
Number of n-node rooted identity trees with thinning limbs and root outdegree (branching factor) 5.
2
1, 4, 11, 28, 70, 160, 366, 804, 1748, 3734, 7918, 16597, 34601, 71628, 147631, 302857, 619231, 1261849, 2564795, 5200248, 10522565, 21252174, 42854194, 86286963, 173517189, 348523105, 699311092, 1401837776, 2807733181, 5619221464, 11238041122, 22460777472
OFFSET
15,2
LINKS
EXAMPLE
a(15) = 1:
: o :
: / ( | ) \ :
: o o o o o :
: | ( ) | | :
: o o o o o :
: | | | :
: o o o :
: | :
: o :
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, add(binomial(A(i, min(i-1, h)), 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=15..50);
CROSSREFS
Column k=5 of A245120.
Sequence in context: A127985 A339252 A005409 * A020964 A113067 A290890
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jul 12 2014
STATUS
approved