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A164983
Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.
0
1, 30, 870, 25230, 731670, 21218430, 615334470, 17844699630, 517496288835, 15007392363600, 435214378179000, 12621216956594400, 366015291433936200, 10614443442672409200, 307818859579059389400, 8926746920297948448000
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170749, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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)/(406*t^8 -
28*t^7 - 28*t^6 - 28*t^5 - 28*t^4 - 28*t^3 - 28*t^2 - 28*t + 1)
MATHEMATICA
coxG[{8, 406, -28}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Oct 27 2016 *)
CROSSREFS
Sequence in context: A163552 A164027 A164666 * A165515 A166026 A166424
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved