A165645 - OEIS

A165645

Number of reduced words of length n in Coxeter group on 33 generators S_i with relations (S_i)^2 = (S_i S_j)^9 = I.

1, 33, 1056, 33792, 1081344, 34603008, 1107296256, 35433480192, 1133871366144, 36283883716080, 1161084278897664, 37154696924185104, 1188950301556638720, 38046409649259331584, 1217485108758599172096, 38959523479708791472128

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OFFSET

0,2

COMMENTS

The initial terms coincide with those of A170752, although the two sequences are eventually different.

Computed with MAGMA using commands similar to those used to compute A154638.

LINKS

Table of n, a(n) for n=0..15.

Index entries for linear recurrences with constant coefficients, signature (31, 31, 31, 31, 31, 31, 31, 31, -496).

FORMULA

G.f. (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)/(496*t^9 - 31*t^8 - 31*t^7 - 31*t^6 - 31*t^5 - 31*t^4 - 31*t^3 -

31*t^2 - 31*t + 1)

CROSSREFS

Sequence in context: A164049 A164669 A165140 * A166129 A166427 A166679

Adjacent sequences: A165642 A165643 A165644 * A165646 A165647 A165648

KEYWORD

nonn

AUTHOR

John Cannon and N. J. A. Sloane, Dec 03 2009

STATUS

approved