|
|
A112838
|
|
Small-number statistic from the enumeration of domino tilings of a 5-pillow of order n.
|
|
11
|
|
|
1, 2, 5, 13, 13, 29, 34, 100, 130, 305, 361, 881, 1145, 2906, 3557, 8669, 10693, 26893, 33680, 83360, 102800, 254565, 317165, 790037, 980237, 2428298, 3011265, 7483801, 9301217, 23092857, 28646722, 71093860
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
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.
Plotting A112838(n+2)/A112838(n) gives an intriguing damped sine curve.
|
|
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
|
|
|
EXAMPLE
|
The number of domino tilings of the 5-pillow of order 6 is 1666=7^2*34. A112838(n)=34.
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005
|
|
STATUS
|
approved
|
|
|
|