OFFSET
0,2
COMMENTS
The generalized polyforms counted by this sequence are "free", which means that they are counted up to rotation and reflection.
LINKS
Peter Kagey, Counting generalized polyominoes
Wikipedia, Snub square tiling
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey and Peter Taylor, Jul 15 2019
EXTENSIONS
a(19)-a(22) from Christian Sievers
STATUS
approved