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A162768
Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.
0
1, 13, 156, 1794, 20592, 235950, 2703558, 30975516, 354897114, 4066164102, 46587289320, 533764778118, 6115505911086, 70067216486124, 802781471013522, 9197712172364430, 105380993789073288, 1207382188488922446
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170732, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
FORMULA
G.f.: (t^3 + 2*t^2 + 2*t + 1)/(66*t^3 - 11*t^2 - 11*t + 1)
CROSSREFS
Sequence in context: A192092 A297454 A102146 * A097827 A163084 A163438
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved