|
%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
|
