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A119611
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Number of free polyominoes in {4,5} tessellation of the hyperbolic plane.
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5
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1, 1, 1, 2, 5, 16, 55, 224, 978, 4507, 21430, 104423, 517897, 2606185, 13272978
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,4
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LINKS
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Eric Weisstein's World of Mathematics, Polyomino.
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EXAMPLE
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For n = 0,1,2,3 the polyominoes in the {4,5} tessellation of the hyperbolic plane are essentially same as the ordinary polyominoes in the plane (A000105), with redefinition of "straight line" and angular deficiency at a vertex.
For n = 4, the square tetromino does not exist. In its place is the cut-square, a pentagonal pentomino with one cell removed.
For n = 5, see links section.
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PROG
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Several working programs are available via the Code Golf Stack Exchange link.
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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a(11)-a(14) from Ed Wynn, Feb 14 2021
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STATUS
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approved
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