

A144553


Number of polyominoes with n cells that have precisely the symmetry group of order 4 generated by 90 degree rotations.


10



0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 3, 2, 0, 0, 12, 7, 0, 0, 44, 25, 0, 0, 165, 90, 0, 0
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OFFSET

1,12


REFERENCES

D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete Math., 36 (1981), 191203.


LINKS

Table of n, a(n) for n=1..27.
Tomas Oliveira e Silva, Enumeration of polyominoes
D. H. Redelmeier, Table 3 of Counting polyominoes...


CROSSREFS

Sequences classifying polyominoes by symmetry group: A000105, A006746, A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.
Sequence in context: A240659 A059033 A133209 * A187130 A187145 A131290
Adjacent sequences: A144550 A144551 A144552 * A144554 A144555 A144556


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane, Jan 01 2009


STATUS

approved



