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Number of 3-dimensional polyominoes (or polycubes) with n cells and rotational symmetry group of order exactly 3.
8

%I #22 Sep 18 2024 16:34:18

%S 0,0,0,1,0,0,4,0,3,24,4,18,151,25,136,992,184,938,6769,1300,6792,47469

%N Number of 3-dimensional polyominoes (or polycubes) with n cells and rotational symmetry group of order exactly 3.

%C This sequence counts "one-sided" polycubes (A000162); chiral polycubes count twice. - _John Mason_, Sep 04 2024

%D 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.

%F a(n) = 2*D(n)+H(n)+FF(n), see Lunnon paper for naming convention. - _John Mason_, Sep 04 2024

%Y See A000162, A066281, A066283, A066287, A066288, A066453, A066454.

%K nonn,more

%O 1,7

%A Brendan Owen (brendan_owen(AT)yahoo.com), Jan 01 2002

%E Name clarified by _John Mason_, Sep 04 2024

%E More terms from _John Mason_, Sep 18 2024