OFFSET
1,2
REFERENCES
Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 2.7, 6.2 and 9.4.
LINKS
Brendan Owen, Polyhouses (gives a(1)-a(10)).
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Oct 10 2011
STATUS
approved