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Revision History for A162210 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Number of reduced words of length n in the Weyl group D_7.
(history; published version)
#16 by Ray Chandler at Wed Feb 21 11:27:09 EST 2024
STATUS

editing

approved

#15 by Ray Chandler at Wed Feb 21 11:27:05 EST 2024
STATUS

approved

editing

#14 by N. J. A. Sloane at Sat Aug 07 13:39:03 EDT 2021
STATUS

editing

approved

#13 by N. J. A. Sloane at Sat Aug 07 13:39:00 EDT 2021
COMMENTS

Computed with MAGMA using commands similar to those used to compute A161409.

LINKS

<a href="/index/Gre#GROWTH">Index entries for growth series for groups</a>

FORMULA

G.f. The growth series for D_m k is the polynomial f(nk) * Product( f(2i), Prod_{i=1..nk-1 )/ } f(12*i)^n, , where f(km) = (1-x^km)/(1-x) [Corrected by _N. J. A. Only finitely many terms are nonzeroSloane_, Aug 07 2021]. This is a row of the triangle in A162206.

MAPLE

# Growth series for D_k, truncated to terms of order M. - N. J. A. Sloane, Aug 07 2021

f := proc(m::integer) (1-x^m)/(1-x) ; end proc:

g := proc(k, M) local a, i; global f;

a:=f(k)*mul(f(2*i), i=1..k-1);

seriestolist(series(a, x, M+1));

end proc;

CROSSREFS
STATUS

approved

editing

#12 by Susanna Cuyler at Wed Mar 25 06:49:29 EDT 2020
STATUS

proposed

approved

#11 by Jean-François Alcover at Wed Mar 25 06:35:02 EDT 2020
STATUS

editing

proposed

#10 by Jean-François Alcover at Wed Mar 25 06:34:58 EDT 2020
MATHEMATICA

n = 7;

x = y + y O[y]^(n^2);

(1-x^n) Product[1-x^(2k), {k, 1, n-1}]/(1-x)^n // CoefficientList[#, y]& (* Jean-François Alcover, Mar 25 2020, from A162206 *)

STATUS

approved

editing

#9 by N. J. A. Sloane at Sun Jan 17 13:11:20 EST 2016
STATUS

editing

approved

#8 by N. J. A. Sloane at Sun Jan 17 13:11:17 EST 2016
CROSSREFS

The growth series for D_k, k >= 5, are A162208-A162212 and A266752-A266754, A162248, A162288, A162297.

STATUS

approved

editing

#7 by N. J. A. Sloane at Sun Jan 10 13:01:50 EST 2016
STATUS

editing

approved