A099112 - OEIS

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A099112

Number of rhombus tilings of a hexagon with all sides of length 2n which contain the rhombus above and next to the center of the hexagon.

6, 73080, 472598638512, 1631619756904447290240, 3008692066440440678503082183460000, 2962701176869736970134706082584757742017500000000 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	LINKS	`M. Fulmek and C. Krattenthaler, [math/9909038] The number of rhombus tilings of a symmetric hexagon which contain a fixed rhombus on the symmetry axis, II`
	PROG	`(PARI) a(n)=(1/3-1/12binomial(2n, n)^3/binomial(6n, 3n))prod(i=1, 2n, prod(j=1, 2n, prod(k=1, 2n, (i+j+k-1)/(i+j+k-2))))`
	CROSSREFS	`Cf. A099112-A099117, A008793.` `Sequence in context: A076913 A101450 A101439 * A172750 A086897 A034208` `Adjacent sequences: A099109 A099110 A099111 * A099113 A099114 A099115`
	KEYWORD	`nonn`
	AUTHOR	`Ralf Stephan, Oct 01 2004`

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Last modified February 14 04:02 EST 2012. Contains 205570 sequences.