A163090 Number of reduced words of length n in Coxeter group on 14 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.

1, 14, 182, 2366, 30667, 397488, 5152056, 66777984, 865538310, 11218616136, 145409328792, 1884713116104, 24428580744204, 316629386210592, 4103970233205024, 53193330778861728, 689461735481280216, 8936411345795737440, 115828687266480560736, 1501305644372339725920

Offset: 0

Author

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

Keywords

• nonn

Comments

The initial terms coincide with those of A170733, 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 (12,12,12,-78).

Programs

Mathematica

CoefficientList[ Series[(t^4 + 2 t^3 + 2 t^2 + 2 t + 1)/(78 t^4 - 12 t^3 - 12 t^2 - 12 t + 1), {t, 0, 20}], t] (* Jinyuan Wang, Mar 22 2020 *)

Formula

G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(78*t^4 - 12*t^3 - 12*t^2 - 12*t + 1).

Extensions

More terms from Jinyuan Wang, Mar 22 2020