OFFSET
0,2
LINKS
Wikipedia, Pentomino
EXAMPLE
a(1) = 4:
._. ._. ._. ._.
|_| | | |_| |_|
|_| | | | | |_|
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|_| | | | | | |
|_| |_| | | | |
|_| |_| |_| | |
|_| |_| |_| |_| .
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 29 2016
STATUS
approved