A165175 Number of reduced words of length n in Coxeter group on 43 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.

1, 43, 1806, 75852, 3185784, 133802928, 5619722976, 236028364992, 9913191328761, 416354035770036, 17486869500749523, 734448518964616428, 30846837793705621380, 1295567187217688816928, 54413821858189144507632

Offset

0,2

Comments

The initial terms coincide with those of A170762, 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 (41, 41, 41, 41, 41, 41, 41, -861).

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)/(861*t^8 -

41*t^7 - 41*t^6 - 41*t^5 - 41*t^4 - 41*t^3 - 41*t^2 - 41*t + 1)

Crossrefs

Sequence in context: A163745 A164113 A164687 * A165694 A166233 A166437

Adjacent sequences: A165172 A165173 A165174 * A165176 A165177 A165178

Keyword

nonn

Author

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

Status

approved