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A163668 Number of reduced words of length n in Coxeter group on 39 generators S_i with relations (S_i)^2 = (S_i S_j)^5 = I. 1
1, 39, 1482, 56316, 2140008, 81319563, 3090115236, 117423309705, 4462045136796, 169556171182476, 6443075832883092, 244834652131935645, 9303632060115383718, 353534798919570074859, 13434200024194718979990 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The initial terms coincide with those of A170758, although the two sequences are eventually different.

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

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..630

Index entries for linear recurrences with constant coefficients, signature (37, 37, 37, 37, -703).

FORMULA

G.f.: (t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(703*t^5 - 37*t^4 - 37*t^3 - 37*t^2 - 37*t + 1).

MATHEMATICA

CoefficientList[Series[(t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(703*t^5 - 37*t^4 - 37*t^3 - 37*t^2 - 37*t + 1), {t, 0, 50}], t] (* G. C. Greubel, Aug 01 2017 *)

PROG

(PARI) t='t+O('t^50); Vec((t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(703*t^5 - 37*t^4 - 37*t^3 - 37*t^2 - 37*t + 1)) \\ G. C. Greubel, Aug 01 2017

CROSSREFS

Sequence in context: A097314 A162871 A163222 * A164084 A164681 A165171

Adjacent sequences:  A163665 A163666 A163667 * A163669 A163670 A163671

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified April 18 17:20 EDT 2019. Contains 322229 sequences. (Running on oeis4.)