|
| |
|
|
A103904
|
|
Number of perfect matchings of an n X (n+1) Aztec rectangle with the third vertex in the topmost row removed.
|
|
2
| |
|
|
1, 2, 24, 384, 10240, 491520, 44040192, 7516192768, 2473901162496, 1583296743997440, 1981583836043018240, 4869940435459321626624, 23574053482485268906770432, 225305087149939210031640608768
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
REFERENCES
| N. Elkies, G. Kuperberg, M. Larsen and J. Propp, Alternating sign matrices and domino tilings, Journal of Algebraic Combinatorics {\bf 1}, 111-132, 219-234 (1992).
|
|
|
LINKS
| M. Ciucu, Enumeration of perfect matchings in graphs with reflective symmetry, J. Combin. Theory Ser. A 77 (1997), no. 1, 67-97
C. Krattenthaler, Schur function identities and the number of perfect matchings of Aztec holey rectangles
H. Helfgott and I. M. Gessel, Enumeration of tilings of diamonds and hexagons with defects
|
|
|
FORMULA
| n(n-1)/2 * 2^(n(n-1)/2), for n>1.
|
|
|
CROSSREFS
| Equals A000217(n-1) * A006125(n). Cf. A095340.
Sequence in context: A081685 A052670 A052736 * A003102 A052712 A133413
Adjacent sequences: A103901 A103902 A103903 * A103905 A103906 A103907
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Ralf Stephan, Feb 21 2005
|
| |
|
|
