A164963 Number of reduced words of length n in Coxeter group on 25 generators S_i with relations (S_i)^2 = (S_i S_j)^8 = I.

1, 25, 600, 14400, 345600, 8294400, 199065600, 4777574400, 114661785300, 2751882840000, 66045187987500, 1585084507560000, 38042028082080000, 913008671585280000, 21912208060815360000, 525892992086016000000

Offset: 0

Author

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

Keywords

• nonn

Comments

The initial terms coincide with those of A170744, although the two sequences are eventually different.

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

Links

• Index entries for linear recurrences with constant coefficients, signature (23, 23, 23, 23, 23, 23, 23, -276).

Programs

Mathematica

coxG[{8,276,-23}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Feb 13 2017 *)

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)/(276*t^8 -

23*t^7 - 23*t^6 - 23*t^5 - 23*t^4 - 23*t^3 - 23*t^2 - 23*t + 1)