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A066287
Number of 3-dimensional polyominoes (or polycubes) with n cells and rotational symmetry group of order exactly 8.
8
0, 1, 1, 2, 2, 1, 1, 2, 4, 2, 5, 7, 8, 5, 10, 17, 20, 12, 23, 42, 48, 30, 59, 108
OFFSET
1,4
COMMENTS
The entry a(14)=2 does not match the examples in A000162, which propose a(14)=5. - R. J. Mathar, Sep 03 2024
The sequence counts "one-sided" polycubes (A000162); chiral polycubes count twice. - John Mason, Sep 04 2024
REFERENCES
W. F. Lunnon, Symmetry of cubical and general polyominoes, pp. 101-108 of R. C. Read, editor, Graph Theory and Computing. Academic Press, NY, 1972.
FORMULA
a(n) = 2*AB(n)+BBC(n), see Lunnon paper for naming convention. - John Mason, Sep 04 2024
KEYWORD
nonn
AUTHOR
Brendan Owen (brendan_owen(AT)yahoo.com), Jan 01 2002
EXTENSIONS
a(14) corrected (after comment from R. J. Mathar), a(15)-a(24) added, and name clarified by John Mason, Sep 04 2024
STATUS
approved