login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112837 Large-number statistic from the enumeration of domino tilings of a 5-pillow of order n. 2
1, 1, 1, 1, 2, 3, 7, 12, 35, 87, 348, 1107, 5518, 22464, 150574, 817057, 7118856, 49644383, 560434040, 5142118400, 76370120248, 914476059335, 17638655014128, 274908897964359, 6936239946318204, 141510942505315328 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

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.

REFERENCES

C. Hanusa (2005). A Gessel-Viennot-Type 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..25.

EXAMPLE

The number of domino tilings of the 5-pillow of order 6 is 1666=7^2*34. A112837(n)=7.

CROSSREFS

A112833 breaks down as A112834^2 times A112835, where A112835 is not necessarily squarefree.

3-pillows: A112833-A112835; 7-pillows: A112839-A112841; 9-pillows: A112842-A112844.

Sequence in context: A034786 A080107 A056156 * A056355 A056356 A084708

Adjacent sequences:  A112834 A112835 A112836 * A112838 A112839 A112840

KEYWORD

nonn

AUTHOR

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 1 02:49 EDT 2021. Contains 346379 sequences. (Running on oeis4.)