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Search: id:A166950
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| A166950 |
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Number of reduced words of length n in Coxeter group on 11 generators S_i with relations (S_i)^2 = (S_i S_j)^13 = I. |
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+0
1
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| 1, 11, 110, 1100, 11000, 110000, 1100000, 11000000, 110000000, 1100000000, 11000000000, 110000000000, 1100000000000, 10999999999945, 109999999998900, 1099999999983555, 10999999999781100, 109999999997266500
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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The initial terms coincide with those of A003953, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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FORMULA
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G,f.: (t^13 + 2*t^12 + 2*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)/(45*t^13 - 9*t^12 - 9*t^11 - 9*t^10 -
9*t^9 - 9*t^8 - 9*t^7 - 9*t^6 - 9*t^5 - 9*t^4 - 9*t^3 - 9*t^2 - 9*t + 1)
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KEYWORD
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nonn,new
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AUTHOR
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John Cannon (john(AT)maths.usyd.edu.au) and N. J. A. Sloane (njas(AT)research.att.com), Dec 03 2009
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