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 A166442 Number of reduced words of length n in Coxeter group on 48 generators S_i with relations (S_i)^2 = (S_i S_j)^11 = I. 1
 1, 48, 2256, 106032, 4983504, 234224688, 11008560336, 517402335792, 24317909782224, 1142941759764528, 53718262708932816, 2524758347319841224, 118663642324032484512, 5577191189229524281440, 262127985893787524168352 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The initial terms coincide with those of A170767, although the two sequences are eventually different. Computed with MAGMA using commands similar to those used to compute A154638. LINKS G. C. Greubel, Table of n, a(n) for n = 0..500 Index entries for linear recurrences with constant coefficients, signature (46, 46, 46, 46, 46, 46, 46, 46, 46, 46, -1081). FORMULA G.f.: (t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(1081*t^11 - 46*t^10 - 46*t^9 - 46*t^8 - 46*t^7 - 46*t^6 - 46*t^5 - 46*t^4 - 46*t^3 - 46*t^2 - 46*t + 1). MATHEMATICA With[{num=Total[2t^Range[10] ]+t^11+1, den=Total[-46 t^Range[10]]+ 1081t^11+ 1}, CoefficientList[Series[num/den, {t, 0, 30}], t]] (* Harvey P. Dale, Jul 21 2011 *) CoefficientList[Series[(x^11 + 2 x^10 + 2 x^9 + 2 x^8 + 2 x^7 + 2 x^6 + 2 x^5 + 2 x^4 + 2 x^3 + 2 x^2 + 2 x + 1)/(1081 x^11 - 46 x^10 - 46 x^9 - 46 x^8 - 46 x^7 - 46 x^6 - 46 x^5 - 46 x^4 - 46 x^3 - 46 x^2 - 46 x + 1), {x, 0, 20}], x] (* Vincenzo Librandi, May 10 2015 *) CROSSREFS Sequence in context: A165180 A165708 A166313 * A166854 A167101 A167645 Adjacent sequences:  A166439 A166440 A166441 * A166443 A166444 A166445 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Dec 03 2009 STATUS approved

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Last modified May 25 05:45 EDT 2019. Contains 323539 sequences. (Running on oeis4.)