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A359520
Number of free holey polyominoes of n cells with simply-connected interiors.
3
0, 0, 0, 0, 0, 0, 1, 5, 35, 179, 909, 4285, 19702, 88040, 386826, 1674852, 7174436, 30462009
OFFSET
1,8
FORMULA
a(n) = A342537(n) - A000104(n) (simply connected polyominoes minus unholey polyominoes).
EXAMPLE
a(7) = 1 because of the holey heptomino.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
John Mason, Jan 04 2023
STATUS
approved