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A164956
Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.
0
1, 22, 462, 9702, 203742, 4278582, 89850222, 1886854662, 39623947671, 832102896240, 17474160719400, 366957372972960, 7706104787608920, 161828199598499280, 3398392171801436040, 71366235192722131200
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170741, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
FORMULA
G.f.: (t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1) / (210*t^8 - 20*t^7 - 20*t^6 - 20*t^5 - 20*t^4 - 20*t^3 - 20*t^2 - 20*t + 1).
CROSSREFS
Sequence in context: A163514 A163988 A164635 * A165364 A165895 A166416
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved