A162833 Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 30, 870, 24795, 706440, 20121360, 573111630, 16323709080, 464941707720, 13242748348620, 377187895691040, 10743291699776160, 305996872843541880, 8715586321562342880, 248242553013255652320, 7070593171000425862320

Offset: 0

Author

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

Keywords

• nonn

Comments

The initial terms coincide with those of A170749, 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 (28, 28, -406).

Programs

Mathematica

coxG[{3,406,-28}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Oct 20 2023 *)

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(406*t^3 - 28*t^2 - 28*t + 1)