function f = f14_6_3(t,x)
a = 3.5; b = 1.3; c = 0.6; d = 0.25;
f = [(x(3) - b)*x(1) - a*x(2); 
     a*x(1) + (x(3)-b)*x(2); 
     c + x(3) - x(3)^3/3 - (x(1)^2 + x(2)^2)*(1 + d*x(3))];
