A162913 Number of reduced words of length n in Coxeter group on 48 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 48, 2256, 104904, 4877472, 226750560, 10541488248, 490066437936, 22782847249104, 1059158680807752, 49239548471206560, 2289112271116376928, 106419233167075660536, 4947355938259459431984, 229999127520543810796752

Offset

0,2

Comments

The initial terms coincide with those of A170767, 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..14.

Index entries for linear recurrences with constant coefficients, signature (46, 46, -1081).

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(1081*t^3 - 46*t^2 - 46*t + 1)

Mathematica

coxG[{3, 1081, -46}] (* The coxG program is at A169452 *) (* or *) LinearRecurrence[{46, 46, -1081}, {1, 48, 2256, 104904}, 30] (* Harvey P. Dale, Dec 30 2017 *)

Crossrefs

Sequence in context: A301859 A233259 A049678 * A156093 A163266 A163829

Adjacent sequences: A162910 A162911 A162912 * A162914 A162915 A162916

Keyword

nonn

Author

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

Status

approved