A162827 Number of reduced words of length n in Coxeter group on 27 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 27, 702, 17901, 456300, 11626875, 296261550, 7548913125, 192350632500, 4901203636875, 124885459968750, 3182152634578125, 81083061181687500, 2066042570916796875, 52643941196224218750, 1341397599294476953125

Offset: 0

Author

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

Keywords

• nonn

Comments

The initial terms coincide with those of A170746, 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 (25, 25, -325).

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(325*t^3 - 25*t^2 - 25*t + 1)