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A166543
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Number of reduced words of length n in Coxeter group on 10 generators S_i with relations (S_i)^2 = (S_i S_j)^12 = I.
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0
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1, 10, 90, 810, 7290, 65610, 590490, 5314410, 47829690, 430467210, 3874204890, 34867844010, 313810596045, 2824295364000, 25418658272400, 228767924419200, 2058911319481200, 18530201872706400, 166771816830738000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| The initial terms coincide with those of A003952, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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FORMULA
| G.f. (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)/(36*t^12 - 8*t^11 - 8*t^10 - 8*t^9 - 8*t^8 -
8*t^7 - 8*t^6 - 8*t^5 - 8*t^4 - 8*t^3 - 8*t^2 - 8*t + 1)
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CROSSREFS
| Sequence in context: A165219 A165788 A166368 * A166933 A167111 A167659
Adjacent sequences: A166540 A166541 A166542 * A166544 A166545 A166546
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KEYWORD
| nonn
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AUTHOR
| 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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