

A164688


Number of reduced words of length n in Coxeter group on 44 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.


0



1, 44, 1892, 81356, 3498308, 150427244, 6468371492, 278139973210, 11960018807352, 514280806967928, 22114074624447960, 950905205618825688, 40888923702614731128, 1758223713235658179896, 75603619412131966509354
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OFFSET

0,2


COMMENTS

The initial terms coincide with those of A170763, 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 (42, 42, 42, 42, 42, 42, 903).


FORMULA

G.f. (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(903*t^7  42*t^6 
42*t^5  42*t^4  42*t^3  42*t^2  42*t + 1)


CROSSREFS

Sequence in context: A163230 A163748 A164277 * A165176 A165695 A166254
Adjacent sequences: A164685 A164686 A164687 * A164689 A164690 A164691


KEYWORD

nonn


AUTHOR

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


STATUS

approved



