OFFSET
1,2
COMMENTS
Also called supertangrams: a generalization of tangrams.
REFERENCES
Martin 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).
LINKS
Ed Pegg, Jr., Illustrations of polyforms
Andrew Clarke, Polyaboloes
Andrew Clarke, Illustration of initial terms
Michael Keller, Counting Polyforms
Henri Picciotto, Geometric Puzzles
Miroslav Vicher, Polyforms
Eric Weisstein's World of Mathematics, Polyabolo
Wikimedia, Polyabolo
CROSSREFS
KEYWORD
nonn,nice,hard,more
AUTHOR
EXTENSIONS
Corrected values for a(8) and a(9), found by Aaron N. 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, Aug 11 2007
Link updated by William Rex Marshall, Dec 16 2009
Modified the definition (what is a "half-square"?) and added a(13), by George Sicherman, Apr 04 2012
a(14) from Juris Cernenoks, Sep 06 2012
a(15) from George Sicherman, Aug 02 2013
a(16)-a(20) from John Mason, Jan 07 2022
a(21) from Aaron N. Siegel, May 17 2022
a(22) from Aaron N. Siegel, Jun 07 2022
STATUS
approved