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 A163084 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I. 0
 1, 13, 156, 1872, 22386, 267696, 3201198, 38280528, 457766166, 5474058876, 65459882202, 782782264836, 9360665698098, 111936698410680, 1338561257884422, 16006781212446024, 191412266920077918, 2288945881199387124, 27371669179630649874, 327315853045229826492 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The initial terms coincide with those of A170732, 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 (11, 11, 11, -66). FORMULA G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(66*t^4 - 11*t^3 - 11*t^2 - 11*t + 1). MATHEMATICA CoefficientList[Series[(t^4+2t^3+2t^2+2t+1)/(66t^4-11t^3-11t^2- 11t+1), {t, 0, 30}], t] (* Harvey P. Dale, Jun 19 2011 *) CROSSREFS Sequence in context: A102146 A162768 A097827 * A163438 A163958 A164610 Adjacent sequences:  A163081 A163082 A163083 * A163085 A163086 A163087 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Dec 03 2009 EXTENSIONS More terms from Harvey P. Dale, Jun 19 2011 STATUS approved

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Last modified October 17 22:05 EDT 2019. Contains 328134 sequences. (Running on oeis4.)