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A089012 a(n) = 1 if n is an exponent of the Weyl group W(E_6), 0 otherwise. 1

%I #13 Oct 13 2017 05:53:49

%S 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,

%T 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,

%U 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

%N a(n) = 1 if n is an exponent of the Weyl group W(E_6), 0 otherwise.

%C 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.

%H Antti Karttunen, <a href="/A089012/b089012.txt">Table of n, a(n) for n = 1..1001</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%F G.f.: (1-x^8)*(1-x^9)/((1-x^3)*(1-x^4)).

%t CoefficientList[Series[(1 - x^8) (1 - x^9)/((1 - x^3) (1 - x^4)), {x, 0, 11}], x] (* _Michael De Vlieger_, Oct 10 2017 *)

%o (Scheme) (define (A089012 n) (if (member n '(1 4 5 7 8 11)) 1 0)) ;; _Antti Karttunen_, Oct 10 2017

%Y Characteristic function of A005556.

%K easy,nonn

%O 1,1

%A _Paul Boddington_, Nov 03 2003

%E More zeros from _Antti Karttunen_, Oct 10 2017

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Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)