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A165365
Number of reduced words of length n in Coxeter group on 23 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
0
1, 23, 506, 11132, 244904, 5387888, 118533536, 2607737792, 57370231424, 1262145091075, 27767191998084, 610878223835649, 13439320921695900, 295665060218165484, 6504631323498465696, 143101889088340396368
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170742, 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)/(231*t^9 - 21*t^8 - 21*t^7 - 21*t^6 - 21*t^5 - 21*t^4 - 21*t^3 -
21*t^2 - 21*t + 1)
CROSSREFS
Sequence in context: A163991 A164636 A164957 * A165939 A166417 A166610
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved