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A071091 Number of tilings by lozenges of hexagon with sides 2n, 2n+3, 2n, 2n+3, 2n, 2n+3 and middle triangle in each edge removed. 0
1, 6272, 23763455716, 55031753041200000000, 73940670068249096897010952625900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

J. Propp, Enumeration of matchings: problems and progress, pp. 255-291 in L. J. Billera et al., eds, New Perspectives in Algebraic Combinatorics, Cambridge, 1999 (see Problem 2).

LINKS

Table of n, a(n) for n=1..5.

M. Ciucu et al., Enumeration of lozenge tilings of hexagons with a central triangular hole, arXiv:math/9912053 [math.CO], 1999.

J. Propp, Update on Enumeration of Matchings, 2009.

J. Propp, Enumeration of matchings: problems and progress, in L. J. Billera et al. (eds.), New Perspectives in Algebraic Combinatorics

CROSSREFS

Sequence in context: A234440 A254635 A189655 * A209826 A107582 A213869

Adjacent sequences:  A071088 A071089 A071090 * A071092 A071093 A071094

KEYWORD

nonn,changed

AUTHOR

N. J. A. Sloane, May 28 2002

STATUS

approved

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Last modified November 26 12:37 EST 2020. Contains 338639 sequences. (Running on oeis4.)