OFFSET
0,3
COMMENTS
Bifurcating node is one that branches to two alive nodes in the next generation (level) of the tree.
FORMULA
EXAMPLE
a(2) = 2 because in the binary tree illustrated in A293230, there are two nodes at the level 2 (namely 5 and 7) that spawn two offspring each.
PROG
(PARI) \\ See program at A293520.
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 12 2017
STATUS
approved