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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.)