close all, clear all, clc
N = 7;
M = N + 4;
B = comb(N);
A = [1 -1];
xn = [1 zeros(1, M)];
n = 0:M;
yn = filter(B, A, xn);
subplot(2,1,1), stem(n, xn), grid
subplot(2,1,2), stem(n, yn), grid