

A165131


Number of reduced words of length n in Coxeter group on 32 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.


0



1, 32, 992, 30752, 953312, 29552672, 916132832, 28400117792, 880403651056, 27292513167360, 846067907712000, 26228105124311040, 813071258396052480, 25205208996092344320, 781361478439118914560, 24222205817980629811200
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OFFSET

0,2


COMMENTS

The initial terms coincide with those of A170751, 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..15.
Index entries for linear recurrences with constant coefficients, signature (30, 30, 30, 30, 30, 30, 30, 465).


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)/(465*t^8 
30*t^7  30*t^6  30*t^5  30*t^4  30*t^3  30*t^2  30*t + 1)


CROSSREFS

Sequence in context: A163565 A164036 A164668 * A165548 A166128 A166426
Adjacent sequences: A165128 A165129 A165130 * A165132 A165133 A165134


KEYWORD

nonn


AUTHOR

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


STATUS

approved



