prefix = "92313" middle_range = 5 suffix = "89" def consecutive(digits, character): rang = "" for zero in range(digits): rang += character return rang filename = prefix + consecutive(middle_range,"x") + suffix + ".txt" open(filename, "w").write('') # emptify file if exists with open(filename, "a") as file: for mid_num in range(int(consecutive(middle_range, "9"))): digits = middle_range - len(str(mid_num)) number = prefix + str(mid_num) + suffix if digits > 0: number = prefix + consecutive(digits, "0") + str(mid_num) + suffix print(number) file.write(number+"\n")