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A357647
a(n) is the number of free unholey polyominoes of n cells with 90-degree rotational symmetry and no other.
2
0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 2, 0, 0, 7, 7, 0, 0, 22, 24, 0, 0, 71, 82, 0, 0, 239, 280, 0, 0, 817, 970, 0, 0, 2841, 3403, 0, 0, 10027, 12064, 0, 0, 35800, 43193, 0, 0, 129007, 156011, 0, 0, 468541, 567664, 0, 0, 1713174
OFFSET
1,12
CROSSREFS
Sequence in context: A121178 A175917 A320525 * A069971 A167291 A063865
KEYWORD
nonn
AUTHOR
John Mason, Oct 10 2022
STATUS
approved