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A165687
Number of reduced words of length n in Coxeter group on 38 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.
0
1, 38, 1406, 52022, 1924814, 71218118, 2635070366, 97497603542, 3607411331054, 133474219248295, 4938546112160904, 182726206148991744, 6760869627477111480, 250152176215336551984, 9255630519918739230696
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170757, 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)/(666*t^9 - 36*t^8 - 36*t^7 - 36*t^6 - 36*t^5 - 36*t^4 - 36*t^3 -
36*t^2 - 36*t + 1)
MATHEMATICA
coxG[{9, 666, -36}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Oct 09 2018 *)
CROSSREFS
Sequence in context: A164071 A164674 A165170 * A166170 A166432 A166690
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved