[seqfan] Planar distributive lattices

[Allan Wechsler]

I forget how I stumbled on this:
https://math.chapman.edu/~jipsen/mathposters/Planar%20distributive%20lattices%20up%20to%20size%2011.pdf
.

It is a chart purporting to show all of the planar distributive lattices
with up to 11 vertices. Like any true-hearted sequence fanatic I counted
the number of these guys of each order, and got the following sequence:

1,1,1,2,3,5,8,14,24,42,72...

Imagine my surprise at finding this sequence missing from OEIS! The author
is apparently Dr. Peter Jipsen, at Chapman University in California.

Perhaps someone here can figure out (a) what a planar distributive lattice
is, (b) whether Dr. Jipsen enumerated them correctly, (c) whether I counted
them off Jipsen's poster correctly, and (d) whether to add the sequence.

Thank you!