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A163055
Number of reduced words of length n in Coxeter group on 12 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I.
0
1, 12, 132, 1452, 15906, 174240, 1908720, 20908800, 229042770, 2509019700, 27484733100, 301077971700, 3298119892650, 36128829891000, 395768617233000, 4335396381723000, 47491541694374250, 520239981289297500
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A003954, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
FORMULA
G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(55*t^4 - 10*t^3 - 10*t^2 - 10*t + 1)
MATHEMATICA
coxG[{4, 55, -10}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Jul 03 2020 *)
CROSSREFS
Sequence in context: A097826 A010580 A010577 * A163432 A163957 A063813
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved