A089010 - OEIS

%I #10 Dec 26 2018 16:53:36

%S 1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,

%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

%N a(n) = 1 if n is an exponent of the Weyl group W(E_8), 0 otherwise.

%C The exponents are 1, 7, 11, 13, 17, 19, 23, 29. The point of this sequence is that a similar generating function gives the exponents for any finite Coxeter group.

%H Antti Karttunen, <a href="/A089010/b089010.txt">Table of n, a(n) for n = 1..10000</a>

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

%F G.f.: x*(1-x^20)*(1-x^24)/((1-x^6)*(1-x^10)).

%t PadRight[CoefficientList[Series[x(1-x^20)(1-x^24)/((1-x^6)(1-x^10)),{x,0,120}],x],120,0] (* _Harvey P. Dale_, May 15 2018 *)

%o (PARI) Vec(x*(1-x^20)*(1-x^24)/((1-x^6)*(1-x^10)) + O(x^90)) \\ _Michel Marcus_, Aug 19 2015

%Y Cf. A005776, A089011.

%K easy,nonn

%O 1,1

%A _Paul Boddington_, Nov 03 2003