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 A164815 Number of reduced words of length n in Coxeter group on 13 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I. 0
 1, 13, 156, 1872, 22464, 269568, 3234816, 38817792, 465813426, 5589760176, 67077110958, 804925197648, 9659100765600, 115909189913088, 1390910047667712, 16690917796540416, 200290980252825462 (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, 11, 11, 11, 11, -66). 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)/(66*t^8 - 11*t^7 - 11*t^6 - 11*t^5 - 11*t^4 - 11*t^3 - 11*t^2 - 11*t + 1) MATHEMATICA With[{num=Total[2t^Range]+t^8+1, den=Total[-11 t^Range]+66t^8+1}, CoefficientList[Series[num/den, {t, 0, 30}], t]] (* Harvey P. Dale, Aug 21 2011 *) CROSSREFS Sequence in context: A163438 A163958 A164610 * A165269 A165873 A166377 Adjacent sequences:  A164812 A164813 A164814 * A164816 A164817 A164818 KEYWORD nonn AUTHOR John Cannon and N. J. A. Sloane, Dec 03 2009 STATUS approved

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Last modified September 15 20:35 EDT 2019. Contains 327087 sequences. (Running on oeis4.)