import matplotlib.pyplot as plt

def theta(n,x) :
    r = 1
    for k in range(1,n+1) :
        r *= (1-x**(2**k))
    return r
    
def dessin(n) :
    X = np.linspace(-1,1,100)
    for k in range(1,n+1) :
        Y = []
        for x in X :
            Y.append(theta(k,x))
        plt.plot(X,Y)
    plt.show()
    
def coeff(n) :
    L = [1,-1]
    for k in range(1,n+1) :
        L += [L[k],-L[k]]
    return L[:n]