OFFSET
1,2
COMMENTS
In a rooted binary tree each vertex has 0 or 2 children.
All terms are even since each pair of 2 child vertices are at the same depth.
LINKS
Kevin Ryde, PARI/GP Code
EXAMPLE
For n=3, tree number 3 and the depth of each of its vertices is
0 root
/ \
1 1 total depths
/ \ a(3) = 0 + 1+1 + 2+2 = 6
2 2
PROG
(PARI) See links.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Kevin Ryde, Oct 11 2022
STATUS
approved