

A164692


Number of reduced words of length n in Coxeter group on 47 generators S_i with relations (S_i)^2 = (S_i S_j)^7 = I.


0



1, 47, 2162, 99452, 4574792, 210440432, 9680259872, 445291953031, 20483429789700, 942237768039885, 43342937224664220, 1993775107496711580, 91713654722307975840, 4218828106989292074000, 194066092450611195098040
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OFFSET

0,2


COMMENTS

The initial terms coincide with those of A170766, 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 (45, 45, 45, 45, 45, 45, 1035).


FORMULA

G.f. (t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(1035*t^7  45*t^6 
45*t^5  45*t^4  45*t^3  45*t^2  45*t + 1)


CROSSREFS

Sequence in context: A163265 A163803 A164332 * A165179 A165703 A166308
Adjacent sequences: A164689 A164690 A164691 * A164693 A164694 A164695


KEYWORD

nonn


AUTHOR

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


STATUS

approved



