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A373635
Number of free n-celled polyominoes to which two inequivalent cells can be adjoined such that the two resulting free (n+1)-celled polyominoes are identical.
3
0, 0, 0, 0, 1, 1, 0, 0, 4, 6, 2, 0, 17, 29
OFFSET
1,9
COMMENTS
Two cells that can be adjoined to an n-celled polyomino are equivalent if there is an isomorphism between the two resulting (n+1)-celled polyominoes that maps the adjoined cell of the first to the adjoined cell of the second.
EXAMPLE
The smallest example is the P pentomino shown below. The two free hexominoes obtained by adjoining one of the two cells marked "*" are identical, but there is no isomorphism between them that also maps the marked cell of the first to the marked cell of the second.
_ _
*| |
| _|*
|_|
CROSSREFS
KEYWORD
nonn,more
AUTHOR
STATUS
approved