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Search: id:A112836
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| A112836 |
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Number of domino tilings of a 5-pillow of order n. |
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11
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| 1, 2, 5, 13, 52, 261, 1666, 14400, 159250, 2308545, 43718544, 1079620569, 34863330980, 1466458546176, 80646187346132, 5787269582487581, 541901038236234048, 66279540183479379277, 10578427028263503488000
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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A 5-pillow is a generalized Aztec pillow. The 5-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 5 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 5-pillow of order 6 is 1666=7^2*34.
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CROSSREFS
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A112836 breaks down as A112837^2 times A112838, where A112838 is not necessarily square-free.
3-pillows: A112833-A112835; 7-pillows: A112839-A112841; 9-pillows: A112842-A112844.
Sequence in context: A098716 A082938 A059103 this_sequence A105905 A075738 A076999
Adjacent sequences: A112833 A112834 A112835 this_sequence A112837 A112838 A112839
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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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