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 A164696 Number of reduced words of length n in Coxeter group on 3 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I. 0
 1, 3, 6, 12, 24, 48, 96, 192, 381, 756, 1503, 2988, 5940, 11808, 23472, 46656, 92742, 184353, 366456, 728439, 1447986, 2878296, 5721456, 11373072, 22607316, 44938668, 89328777, 177567132, 352966731, 701624856, 1394685096, 2772345504 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The initial terms coincide with those of A003945, although the two sequences are eventually different. Computed with MAGMA using commands similar to those used to compute A154638. LINKS Index entries for linear recurrences with constant coefficients, signature (1, 1, 1, 1, 1, 1, 1, -1). 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)/(t^8 - t^7 - t^6 - t^5 - t^4 - t^3 - t^2 - t + 1) MATHEMATICA With[{num=Total[2t^Range]+t^8+1, den=Total[-t^Range]+t^8+1}, CoefficientList[ Series[ num/den, {t, 0, 40}], t]] (* Harvey P. Dale, Aug 05 2011 *) CROSSREFS Sequence in context: A164352 A115829 A115805 * A165183 A046944 A165745 Adjacent sequences:  A164693 A164694 A164695 * A164697 A164698 A164699 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Dec 03 2009 STATUS approved

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Last modified May 7 00:22 EDT 2021. Contains 343609 sequences. (Running on oeis4.)