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Search: id:A098912
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| A098912 |
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Number of ways angles from pi/n to (n-1)pi/n can tile around a vertex, where rotations and reflections of an angle sequence are not counted. |
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2
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OFFSET
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2,2
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COMMENT
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Sequence can be interpreted as a tiling of rhombs (with appropriate angles) around a vertex. E.g.. a(5) is the number of ways Penrose rhombs can tile around a vertex
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EXAMPLE
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a(3) = 5 because we can write 2pi = 2'+2'+2' or 2'+1'+2'+1' or 2'+2'+1'+1' or 2'+1'+1'+1'+1' or 1'+1'+1'+1'+1'+1' where k' = k pi/3
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CROSSREFS
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Cf. A091696, A098913.
Sequence in context: A108300 A041469 A089102 this_sequence A120343 A057553 A006217
Adjacent sequences: A098909 A098910 A098911 this_sequence A098913 A098914 A098915
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KEYWORD
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nonn
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AUTHOR
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Stuart E Anderson (stuart(AT)squaring.net), Oct 17 2004
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