A162835 - OEIS

A162835

Number of reduced words of length n in Coxeter group on 31 generators S_i with relations (S_i)^2 = (S_i S_j)^3 = I.

1, 31, 930, 27435, 809100, 23854965, 703323660, 20736221625, 611369903490, 18025131836235, 531438294045150, 15668493442542015, 461957088012265560, 13619966204279779425, 401559980828963528040, 11839267130678720397885

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OFFSET

0,2

COMMENTS

The initial terms coincide with those of A170750, 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 (29, 29, -435).

FORMULA

G.f.: (t^3 + 2*t^2 + 2*t + 1)/(435*t^3 - 29*t^2 - 29*t + 1)

MATHEMATICA

coxG[{3, 435, -29}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Jan 18 2021 *)

CROSSREFS

Sequence in context: A202977 A213467 A157878 * A163214 A163564 A164030

Adjacent sequences: A162832 A162833 A162834 * A162836 A162837 A162838

KEYWORD

nonn

AUTHOR

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

STATUS

approved