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A165282 Number of reduced words of length n in Coxeter group on 15 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I. 0
1, 15, 210, 2940, 41160, 576240, 8067360, 112943040, 1581202560, 22136835735, 309915698820, 4338819763005, 60743476395420, 850408665522780, 11905721261135520, 166680096869329680, 2333521345158669120 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The initial terms coincide with those of A170734, although the two sequences are eventually different.

Computed with MAGMA using commands similar to those used to compute A154638.

LINKS

Table of n, a(n) for n=0..16.

Index entries for linear recurrences with constant coefficients, signature (13, 13, 13, 13, 13, 13, 13, 13, -91).

FORMULA

G.f. (t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t +

1)/(91*t^9 - 13*t^8 - 13*t^7 - 13*t^6 - 13*t^5 - 13*t^4 - 13*t^3 -

13*t^2 - 13*t + 1)

CROSSREFS

Sequence in context: A163962 A164626 A164860 * A165875 A166382 A166583

Adjacent sequences:  A165279 A165280 A165281 * A165283 A165284 A165285

KEYWORD

nonn

AUTHOR

John Cannon and N. J. A. Sloane, Dec 03 2009

STATUS

approved

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Last modified November 18 14:55 EST 2019. Contains 329262 sequences. (Running on oeis4.)