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A089012
a(n) = 1 if n is an exponent of the Weyl group W(E_6), 0 otherwise.
1
1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
1,1
COMMENTS
The exponents are 1, 4, 5, 7, 8, 11. The point of this sequence is that a similar generating function gives the exponents for any finite Coxeter group.
FORMULA
G.f.: (1-x^8)*(1-x^9)/((1-x^3)*(1-x^4)).
MATHEMATICA
CoefficientList[Series[(1 - x^8) (1 - x^9)/((1 - x^3) (1 - x^4)), {x, 0, 11}], x] (* Michael De Vlieger, Oct 10 2017 *)
PROG
(Scheme) (define (A089012 n) (if (member n '(1 4 5 7 8 11)) 1 0)) ;; Antti Karttunen, Oct 10 2017
CROSSREFS
Characteristic function of A005556.
Sequence in context: A285305 A372574 A028863 * A083035 A359422 A356161
KEYWORD
easy,nonn
AUTHOR
Paul Boddington, Nov 03 2003
EXTENSIONS
More zeros from Antti Karttunen, Oct 10 2017
STATUS
approved