A162803 Number of reduced words of length n in Coxeter group on 17 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 17, 272, 4216, 65280, 1009800, 15620280, 241617600, 3737392200, 57810713400, 894227472000, 13832085717000, 213957412227000, 3309535172520000, 51192538485165000, 791856215398035000, 12248587087545600000

Offset: 0

Author

John Cannon and N. J. A. Sloane, Dec 03 2009

Keywords

• nonn

Comments

The initial terms coincide with those of A170736, although the two sequences are eventually different.

Computed with MAGMA using commands similar to those used to compute A154638.

Links

• Index entries for linear recurrences with constant coefficients, signature (15, 15, -120).

Programs

Mathematica

coxG[{3,120,-15}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Aug 08 2017 *)

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(120*t^3 - 15*t^2 - 15*t + 1)