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A167961
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Number of reduced words of length n in Coxeter group on 45 generators S_i with relations (S_i)^2 = (S_i S_j)^16 = I.
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0
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1, 45, 1980, 87120, 3833280, 168664320, 7421230080, 326534123520, 14367501434880, 632170063134720, 27815482777927680, 1223881242228817920, 53850774658067988480, 2369434084954991493120, 104255099738019625697280
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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 A170764, 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..14.
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FORMULA
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G.f. (t^16 + 2*t^15 + 2*t^14 + 2*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)/(946*t^16 -
43*t^15 - 43*t^14 - 43*t^13 - 43*t^12 - 43*t^11 - 43*t^10 - 43*t^9 -
43*t^8 - 43*t^7 - 43*t^6 - 43*t^5 - 43*t^4 - 43*t^3 - 43*t^2 - 43*t + 1)
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CROSSREFS
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Sequence in context: A170582 A170630 A170678 A170726 A170764 A218747 A121009
Adjacent sequences: A167958 A167959 A167960 * A167962 A167963 A167964
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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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