OFFSET
0,2
COMMENTS
If the zeros are ignored, this is the coordination sequence for the truncated cuboctahedron (see the Karzes link). - N. J. A. Sloane, Jan 08 2020
Computed with MAGMA using commands similar to those used to compute A161409.
REFERENCES
J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
N. Bourbaki, Groupes et algèbres de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)
LINKS
FORMULA
G.f. for B_m is the polynomial Prod_{k=1..m}(1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.
MAPLE
seq(coeff(series(mul((1-x^(2k))/(1-x), k=1..3), x, n+1), x, n), n = 0 .. 120); # Muniru A Asiru, Oct 25 2018
MATHEMATICA
CoefficientList[Series[Product[(1-x^(2*k)), {k, 1, 3}] /(1-x)^3, {x, 0, 9}], x] (* G. C. Greubel, Oct 25 2018 *)
PROG
(PARI) t='t+O('t^10); Vec(prod(k=1, 3, 1-t^(2*k))/(1-t)^3) \\ G. C. Greubel, Oct 25 2018
(Magma) m:=10; R<t>:=PowerSeriesRing(Integers(), m); Coefficients(R!((&*[1-t^(2*k): k in [1..3]])/(1-t)^3)); // G. C. Greubel, Oct 25 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Nov 30 2009
STATUS
approved