OFFSET
0,5
COMMENTS
Although the cocoon concertina n-cube has no ranks for n>2, its inner vertices can be forced on the rank layers of the convex solid.
Sum of row n is the number of vertices of a cocoon concertina n-cube, i.e., A000696(n).
The rows are palindromic. Their lengths are the central polygonal numbers A000124 = 1, 2, 4, 7, 11, 16, 22, ... That means after row 0 rows of even and odd length follow each other in pairs.
A300699 is a triangle of the same shape that shows the number of ranks in convex concertina hypercubes.
LINKS
Tilman Piesk, Python code used to generate the sequence (currently unfinished, does not find all ranks for n>3)
EXAMPLE
First rows of the triangle:
k 0 1 2 3 4 5 6
n
0 1
1 1 1
2 1 3 3 1
3 1 6 13 6 13 6 1
CROSSREFS
KEYWORD
nonn,tabf,more
AUTHOR
Tilman Piesk, Mar 13 2018
STATUS
approved