OFFSET
1,4
COMMENTS
These are n-cell polyhexes with the perimeter less than the maximum possible one.
If we associate a graph to a polyhex with vertices representing cells and edges representing two cells with a common edge, then this sequence enumerates polyhexes whose corresponding graphs have cycles.
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Tanya Khovanova, Mar 03 2008
STATUS
approved