A164835 Number of reduced words of length n in Coxeter group on 14 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.

1, 14, 182, 2366, 30758, 399854, 5198102, 67575326, 878479147, 11420227728, 148462945176, 1930018088544, 25090232567400, 326172989788464, 4240248430609464, 55123223921595648, 716601837188495622

Offset

0,2

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

Table of n, a(n) for n=0..16.

Index entries for linear recurrences with constant coefficients, signature (12, 12, 12, 12, 12, 12, 12, -78).

Formula

G.f.: (t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(78*t^8 - 12*t^7 - 12*t^6 - 12*t^5 - 12*t^4 - 12*t^3 - 12*t^2 - 12*t + 1).

Mathematica

coxG[{8, 78, -12}] (* The coxG program is at A169452 *) (* Harvey P. Dale, May 26 2017 *)

Crossrefs

Sequence in context: A163439 A163959 A164618 * A165270 A165874 A166379

Adjacent sequences: A164832 A164833 A164834 * A164836 A164837 A164838

Keyword

nonn

Author

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

Status

approved