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A163110 Number of reduced words of length n in Coxeter group on 19 generators S_i with relations (S_i)^2 = (S_i S_j)^4 = I. 0
1, 19, 342, 6156, 110637, 1988388, 35735751, 642249324, 11542621410, 207446086881, 3728258709552, 67004941956759, 1204224973728534, 21642549713419572, 388963830112221249, 6990528525469894908, 125635046969043641691, 2257935858412484688900, 40580032910411799982386 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
The initial terms coincide with those of A170738, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
LINKS
FORMULA
G.f.: (t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(153*t^4 - 17*t^3 - 17*t^2 - 17*t + 1).
MATHEMATICA
coxG[{4, 153, -17}] (* The coxG program is at A169452 *) (* Harvey P. Dale, Aug 24 2019 *)
PROG
(PARI) Vec((t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(153*t^4 - 17*t^3 - 17*t^2 - 17*t + 1) + O(t^20)) \\ Jinyuan Wang, Mar 23 2020
CROSSREFS
Sequence in context: A049629 A162805 A049664 * A163453 A163968 A164631
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
EXTENSIONS
More terms from Jinyuan Wang, Mar 23 2020
STATUS
approved

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Last modified March 4 16:44 EST 2024. Contains 370532 sequences. (Running on oeis4.)