

A112836


Number of domino tilings of a 5pillow of order n.


11



1, 2, 5, 13, 52, 261, 1666, 14400, 159250, 2308545, 43718544, 1079620569, 34863330980, 1466458546176, 80646187346132, 5787269582487581, 541901038236234048, 66279540183479379277, 10578427028263503488000
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OFFSET

0,2


COMMENTS

A 5pillow is a generalized Aztec pillow. The 5pillow of order n is a rotationallysymmetric 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.


REFERENCES

C. Hanusa (2005). A GesselViennotType Method for Cycle Systems with Applications to Aztec Pillows. PhD Thesis. University of Washington, Seattle, USA.


LINKS

Table of n, a(n) for n=0..18.


EXAMPLE

The number of domino tilings of the 5pillow of order 6 is 1666=7^2*34.


CROSSREFS

A112836 breaks down as A112837^2 times A112838, where A112838 is not necessarily squarefree.
3pillows: A112833A112835; 7pillows: A112839A112841; 9pillows: A112842A112844.
Sequence in context: A303792 A059103 A260709 * A105905 A236513 A214853
Adjacent sequences: A112833 A112834 A112835 * A112837 A112838 A112839


KEYWORD

nonn


AUTHOR

Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005


STATUS

approved



