

A164959


Number of reduced words of length n in Coxeter group on 24 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.


0



1, 24, 552, 12696, 292008, 6716184, 154472232, 3552861336, 81715810452, 1879463634048, 43227663437376, 994236255707904, 22867433804191680, 525950975723336064, 12096872400856060224, 278228064281733992448
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OFFSET

0,2


COMMENTS

The initial terms coincide with those of A170743, 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 (22, 22, 22, 22, 22, 22, 22, 253).


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)/(253*t^8 
22*t^7  22*t^6  22*t^5  22*t^4  22*t^3  22*t^2  22*t + 1)


CROSSREFS

Sequence in context: A163519 A163992 A164637 * A165366 A165965 A166418
Adjacent sequences: A164956 A164957 A164958 * A164960 A164961 A164962


KEYWORD

nonn


AUTHOR

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


STATUS

approved



