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A122722 Number of triangulations of Delta^2 x Delta^(k-1). 0
1, 6, 108, 4488, 376200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The number of triangulations of Delta^2 x Delta^(k) is between alpha^k^2 and beta*(k^2) where alpha = (27/16)^(1/4) ~ 1.13975 and beta = 6^(1/6) ~1.34800 [Santos, p. 10].

There are arithmetic errors in Santos' lecture notes. The same table gives lozenge tilings of k*Delta^2.

LINKS

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

J. A. de Loera, J. Rambau and Francisco Santos, MSRI Summer School on Triangulations of point sets, Applications, Structures and Algorithms.

Francisco Santos, Enumeration in the space of triangulations, part 1. Handwritten; table on p. 9.

EXAMPLE

a(1) = 1 * 1! = 1.

a(2) = 3 * 2! = 6.

a(3) = 18 * 3! = 108.

a(4) = "187 * 4! = 2244" [sic]; actually 187 * 4! = 4488.

a(5) = "3135 * 5! = 18400" [sic]; actually 3135 * 5! = 376200.

CROSSREFS

Sequence in context: A221954 A167484 A011555 * A127946 A012503 A168482

Adjacent sequences:  A122719 A122720 A122721 * A122723 A122724 A122725

KEYWORD

nonn

AUTHOR

Jonathan Vos Post, Oct 22 2006

STATUS

approved

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Last modified August 18 00:56 EDT 2019. Contains 326059 sequences. (Running on oeis4.)