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A006074
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Number of polyaboloes (or polytans): number of different shapes that can be formed with n half-squares.
(Formerly M2379)
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2
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1, 3, 4, 14, 30, 107, 318, 1116, 3743, 13240, 46476, 166358
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Also called supertangrams: a generalization of tangrams.
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REFERENCES
| M. Gardner, Mathematical Magic Show. Random House, NY, 1978, p. 151 (but beware errors).
T. H. O'Beirne, New Scientist, 266 (Dec. 21, 1961), p. 752.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Ed Pegg, Jr., Illustrations of polyforms
A. Clarke, Polyaboloes
A. Clarke, Illustration of initial terms
M. Keller, Counting Polyforms
H. Picciotto, Geometric Puzzles
M. Vicher, Polyforms
Eric Weisstein's World of Mathematics, Polyabolo.
Author? Polyaboloes.
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CROSSREFS
| Sequence in context: A080878 A110565 A057433 * A081714 A117718 A176857
Adjacent sequences: A006071 A006072 A006073 * A006075 A006076 A006077
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KEYWORD
| nonn,nice,hard
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Corrected values for a(8) and a(9), found by Aaron Siegel and confirmed by a Japanese puzzlist named Taro, reported by Michael Keller (Wgreview(AT)aol.com), Sep 02 2000
One more term from Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 11 2007
Link updated by William Rex Marshall (w.r.marshall(AT)actrix.co.nz), Dec 16 2009
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