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A165364
Number of reduced words of length n in Coxeter group on 22 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
0
1, 22, 462, 9702, 203742, 4278582, 89850222, 1886854662, 39623947902, 832102905711, 17474161015080, 366957381215040, 7706105003381400, 161828205026186160, 3398392304608621320, 71366238377013998880
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^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)/(210*t^9 - 20*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: A163988 A164635 A164956 * A165895 A166416 A166608
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved