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 A217153 Number of nontrivially compound perfect squared rectangles of order n up to symmetries of the rectangle. 9
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 48, 264, 1256, 5396, 22540, 92060, 370788 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,13 COMMENTS A squared rectangle (which may be a square) is a rectangle dissected into a finite number, two or more, of squares. If no two of these squares have the same size the squared rectangle is perfect. The order of a squared rectangle is the number of constituent squares. A squared rectangle is simple if it does not contain a smaller squared rectangle, compound if it does, and trivially compound if a constituent square has the same side length as a side of the squared rectangle under consideration. LINKS I. Gambini, Quant aux carres carreles, Thesis, Universite de la Mediterranee Aix-Marseille II, 1999, p. 24. [Number of compound rectangles includes any that comprises a square sandwiched between two rectangles (from order 19) and excludes squares in separate column (order 24).] CROSSREFS Cf. A217152 (counts symmetries of squared subrectangles as equivalent). Cf. A002839, A181340, A217154, A217155. Sequence in context: A292074 A127211 A274729 * A129002 A291623 A144704 Adjacent sequences:  A217150 A217151 A217152 * A217154 A217155 A217156 KEYWORD nonn,hard,more AUTHOR Geoffrey H. Morley, Sep 27 2012 EXTENSIONS a(19) and a(20) corrected (thanks to Stuart E Anderson's computations which show I misinterpreted Gambini's counts) by Geoffrey H. Morley, Oct 12 2012 STATUS approved

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Last modified January 24 04:31 EST 2018. Contains 298115 sequences.