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A164974 Number of reduced words of length n in Coxeter group on 29 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I. 0
1, 29, 812, 22736, 636608, 17825024, 499100672, 13974818816, 391294926442, 10956257929008, 306775221694326, 8589706198539984, 240511773309887520, 6734329645698353664, 188561229884155989504, 5279714431285226139648 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The initial terms coincide with those of A170748, 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 (27, 27, 27, 27, 27, 27, 27, -378).

FORMULA

G.f. (t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(378*t^8 -

27*t^7 - 27*t^6 - 27*t^5 - 27*t^4 - 27*t^3 - 27*t^2 - 27*t + 1)

MATHEMATICA

coxG[{8, 378, -27}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Aug 26 2017 *)

CROSSREFS

Sequence in context: A163549 A164026 A164665 * A165512 A166004 A166423

Adjacent sequences:  A164971 A164972 A164973 * A164975 A164976 A164977

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified October 19 16:17 EDT 2019. Contains 328223 sequences. (Running on oeis4.)