Here is a short Python script to implement method 2 for generating the symbolic code for the nth iteration of the Lévy dragon curve.
n = input("n = ") b = [] code = '' turn = ['R','S','L','B'] for k in range(0,2**n): b += [0] for k in range(1,2**(n-1)): b[2*k] = (b[k] + 1) % 4 for k in range(1,2**n): code = code +' '+ turn[int(b[k])] print(code[1:])