OFFSET
0,4
COMMENTS
A 3-pillow is also called an Aztec pillow. The 3-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 3 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.
EXAMPLE
The number of domino tilings of the 3-pillow of order 4 is 117=3^2*13. A112834(4)=3.
CROSSREFS
KEYWORD
nonn
AUTHOR
Christopher Hanusa (chanusa(AT)math.binghamton.edu), Sep 21 2005
STATUS
approved