OFFSET
1,3
COMMENTS
Any rootward 8-node path starting at a leaf contains the root or a branching node.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
FORMULA
a(n) ~ c * d^n / n^(3/2), where d = 2.95534758805897943282870965508636011438518881375... and c = 0.43969195292137654501555629074396535899093... . - Vaclav Kotesovec, Feb 28 2016
MAPLE
with(numtheory):
g:= proc(n, k) option remember; `if`(n=0, 1, add(add(d*(g(d-1, k)-
`if`(d=k, 1, 0)), d=divisors(j))*g(n-j, k), j=1..n)/n)
end:
a:= n-> g(n-1, 8):
seq(a(n), n=1..40);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 28 2015
STATUS
approved