s = 1/16;%0;%1/128;
a = [-5*s/8, -7*s/8, (3*s + 2)/8, (9*s + 6)/8, (9*s + 6)/8, (3*s + 2)/8, -7*s/8, -5*s/8];

a_(-3) a_(-2) a_(-1) a_(0) a_1  a_2  a_3 a_4

n = 2