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A002881
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Number of simple imperfect squared rectangles of order n.
(Formerly M4614 N1969)
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5
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0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 9, 33, 104, 280, 948, 3014, 9494, 30301, 98889
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,12
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COMMENTS
| The order of a squared rectangle is the number of squares into which it is divided.
A simple squared rectangle contains no smaller rectangle or dissected square in the squared rectangle
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REFERENCES
| C. J. Bouwkamp, personal communication.
M. Gardner, The 2nd Scientific American Book of Mathematical Puzzles and Diversions. Simon and Schuster, NY, 1961, p. 207.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Eric Weisstein's World of Mathematics, Perfect Rectangle
Stuart Anderson Simple Imperfect Squared Rectangles
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CROSSREFS
| Cf. A006983, A002962, A002839, A014530.
Sequence in context: A112888 A048479 A031880 * A036543 A147269 A147123
Adjacent sequences: A002878 A002879 A002880 * A002882 A002883 A002884
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KEYWORD
| hard,nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Stuart E Anderson, 9 March 2011: included 'simple' in the definition, corrected terms a(13), a(15), a(16), a(17), a(18) and extended terms to a(20), gave a definition of 'simple' in the comments. Stuart E Anderson, 10 April 2011: Corrected a(16) to a(20), excess compounds removed, counts final.
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