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Search: id:A112839
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| A112839 |
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Number of domino tilings of a 7-pillow of order n. |
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13
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| 1, 2, 5, 13, 34, 136, 666, 3577, 23353, 200704, 2062593, 24878084, 373006265, 6917185552, 153624835953, 4155902941554, 138450383756352, 5602635336941568, 274540864716936000, 16486029239132118530, 1209110712606533552257
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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A 7-pillow is a generalized Aztec pillow. The 7-pillow of order n is a rotationally-symmetric region. It has a 2 X 2n central band of squares, and then steps up from this band with steps of 7 horizontal squares to every 1 vertical square, and steps down with steps of 1 horizontal square to every 1 vertical square.
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REFERENCES
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C. Hanusa (2005). A Gessel-Viennot-Type Method for Cycle Systems with Applications to Aztec Pillows. PhD Thesis. University of Washington, Seattle, USA.
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EXAMPLE
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The number of domino tilings of the 7-pillow of order 8 is 23353=11^2*193.
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CROSSREFS
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A112839 breaks down as A112840^2 times A112841, where A112841 is not necessarily square-free.
3-pillows: A112833-A112835; 5-pillows: A112836-A112838; 9-pillows: A112842-A112844.
Sequence in context: A064780 A029885 A114298 this_sequence A137674 A048781 A097919
Adjacent sequences: A112836 A112837 A112838 this_sequence A112840 A112841 A112842
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KEYWORD
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nonn
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AUTHOR
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Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005
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