OFFSET
1,2
LINKS
François Bienvenu, Jean-Jil Duchamps, Michael Fuchs, and Tsan-Cheng Yu, The B_2 index of galled trees, arXiv:2407.19454 [q-bio.PE], 2024. See p. 5.
Mathilde Bouvel, Philippe Gambette and Marefatollah Mansouri, Maple worksheet
Mathilde Bouvel, Philippe Gambette and Marefatollah Mansouri, Counting Phylogenetic Networks of level 1 and 2, arXiv:1909.10460 [math.CO], 2019.
FORMULA
Bouvel, Gambette and Mansouri provide (among other results) a closed formula for a(n), an equation and a closed form for the associated exponential generating function, and an asymptotic estimate of a(n). See their Section 5.
EXAMPLE
a(4) = 723 is the number of rooted level-1 phylogenetic networks with 4 labeled leaves.
MAPLE
# see links section
CROSSREFS
KEYWORD
nonn
AUTHOR
Mathilde Bouvel, Oct 04 2019
STATUS
approved