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Search: id:A056842
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| A056842 |
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Number of polydrafters: a(n) is the number of polydrafters with n cells. See the Paterson link for the definition. |
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+0
3
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OFFSET
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1,2
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COMMENT
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Restatement of the definition: A polydrafter is a polygon formed by joining 30-60-90 triangles, according to the following rules:
(a) Two triangles may be joined along their short legs, with their right angles touching;
(b) Two triangles may be joined along their long legs, with their right angles touching;
(c) Two triangles may be joined along their hypotenuses, in either direction;
(d) The short leg of triangle 1 may be joined to half of the hypotenuse of triangle 2, with the right angle of triangle 1 touching the midpoint of the hypotenuse of triangle 2.
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REFERENCES
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Ed Pegg, Jr., Polyform puzzles, in Tribute to a Mathemagician, Peters, 2005, pp. 119-125.
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LINKS
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D. Paterson, Pentominos & Dodecadudes
M. Vicher, Polyforms
M. Vicher, Tridrafters
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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a(3) = 14 because there are 14 tridafters. The second Vicher link shows various arrangements of them.
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CROSSREFS
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Adjacent sequences: A056839 A056840 A056841 this_sequence A056843 A056844 A056845
Sequence in context: A032404 A059954 A139257 this_sequence A130263 A077401 A013314
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KEYWORD
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nonn,more
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AUTHOR
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James A. Sellers (sellersj(AT)math.psu.edu), Aug 28 2000
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EXTENSIONS
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Edited by David R. Wasserman (wasserma(AT)spawar.navy.mil), Dec 01 2003
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