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A166585
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Number of reduced words of length n in Coxeter group on 17 generators S_i with relations (S_i)^2 = (S_i S_j)^12 = I.
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0
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1, 17, 272, 4352, 69632, 1114112, 17825792, 285212672, 4563402752, 73014444032, 1168231104512, 18691697672192, 299067162754936, 4785074604076800, 76561193665194120, 1224979098642551040, 19599665578271938560
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OFFSET
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0,2
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COMMENTS
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The initial terms coincide with those of A170736, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
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LINKS
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Table of n, a(n) for n=0..16.
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FORMULA
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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)/(120*t^12 - 15*t^11 - 15*t^10 - 15*t^9 - 15*t^8
- 15*t^7 - 15*t^6 - 15*t^5 - 15*t^4 - 15*t^3 - 15*t^2 - 15*t + 1)
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CROSSREFS
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Sequence in context: A165321 A165879 A166411 * A167027 A167124 A167673
Adjacent sequences: A166582 A166583 A166584 * A166586 A166587 A166588
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KEYWORD
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nonn
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AUTHOR
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John Cannon (john(AT)maths.usyd.edu.au) and N. J. A. Sloane, Dec 03 2009
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STATUS
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approved
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