A162914 Number of reduced words of length n in Coxeter group on 49 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 49, 2352, 111720, 5306112, 251985048, 11966664360, 568291227840, 26987881799256, 1281641734875432, 60864559478706816, 2890429126368804888, 137265111357893562792, 6518655179668349992512, 309567849623689435185624

Offset

0,2

Comments

The initial terms coincide with those of A170768, 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 (47, 47, -1128).

Formula

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(1128*t^3 - 47*t^2 - 47*t + 1)

Crossrefs

Sequence in context: A245036 A061615 A049682 * A163287 A163835 A164350

Adjacent sequences: A162911 A162912 A162913 * A162915 A162916 A162917

Keyword

nonn

Author

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

Status

approved