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A165547
Number of reduced words of length n in Coxeter group on 31 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
0
1, 31, 930, 27900, 837000, 25110000, 753300000, 22599000000, 677970000000, 20339099999535, 610172999972100, 18305189998744965, 549155699949807900, 16474670998118005500, 494240129932253220000, 14827203897628988250000
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170750, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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)/(435*t^9 - 29*t^8 - 29*t^7 - 29*t^6 - 29*t^5 - 29*t^4 - 29*t^3 -
29*t^2 - 29*t + 1)
CROSSREFS
Sequence in context: A164030 A164667 A164992 * A166075 A166425 A166618
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved