A162743 Number of reduced words of length n in Coxeter group on 6 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 6, 30, 135, 600, 2640, 11610, 51000, 224040, 984060, 4322400, 18985440, 83390760, 366280800, 1608831840, 7066542960, 31038691200, 136332618240, 598819808160, 2630222793600, 11552844224640, 50744069991360

Offset: 0

Author

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

Keywords

• nonn

Comments

The initial terms coincide with those of A003948, 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 (4, 4, -10).

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(10*t^3 - 4*t^2 - 4*t + 1)