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%I #11 May 21 2014 20:02:28
%S 1,1,2,1,3,1,2,-1,3,1,3,1,4,2,-1,-1,1,3,1,4,6,1,-1,-4,5,-3,6,4,9,-4,
%T -5,0,-3,4,4,18,1,-3,-4,-7,0,-3,25,1,5,-11,-4,-12,-7,32,11,15,-15,4,
%U -24,-21,27,21,31,-24,17,-41,-31,4,38,50,-18,36,-46,-41,-36,45,67,-12,57,-50,-38,-95,51,73,14,82,-32,-27,-171,44
%N Let qf(a,q) = Product(1-a*q^j,j=0..infinity); g.f. is qf(q^3,q^7)*qf(q^5,q^7)*qf(q^6,q^7)/(qf(q,q^7)*qf(q^2,q^7)*qf(q^4,q^7)).
%H Alois P. Heinz, <a href="/A111376/b111376.txt">Table of n, a(n) for n = 0..1000</a>
%F Euler transform of period 7 sequence [1, 1, -1, 1, -1, -1, 0, ...]. - _Michael Somos_, Nov 11 2005
%F G.f.: Product_{k>0} (1-x^(7k-4))(1-x^(7k-2))(1-x^(7k-1))/((1-x^(7k-3))*(1-x^(7k-5))(1-x^(7k-6))). - _Michael Somos_, Nov 11 2005
%o (PARI) {a(n)=if(n<0, 0, polcoeff( prod(k=1,n, (1-x^k)^-kronecker(-7,k), 1+x*O(x^n)), n))} /* _Michael Somos_, Nov 11 2005 */
%Y Cf. A111375.
%K sign,look
%O 0,3
%A _N. J. A. Sloane_, Nov 09 2005