OFFSET
0,2
REFERENCES
N. Bourbaki, Groupes et Algèbres de Lie, Chap. 4, 5 and 6, Hermann, Paris, 1968. See Chap. VI, Section 4, Problem 10b, page 231, W_a(t).
J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.
LINKS
Ray Chandler, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7, -21, 34, -28, -1, 34, -48, 34, 0, -35, 56, -62, 57, -41, 15, 15, -39, 43, -19, -20, 50, -61, 57, -43, 28, -22, 21, -16, 12, -17, 26, -30, 26, -17, 12, -16, 21, -22, 28, -43, 57, -61, 50, -20, -19, 43, -39, 15, 15, -41, 57, -62, 56, -35, 0, 34, -48, 34, -1, -28, 34, -21, 7, -1).
FORMULA
The growth series for the affine Coxeter group of type D_k (k >= 3) has g.f. = Product_i (1-x^{m_i+1})/((1-x)*(1-x^{m_i})) where the m_i are [1,3,5,...,2k-3,k-1].
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 10 2016
STATUS
approved