# ### # Pandigital multiples # Problem 38 # # Take the number 192 and multiply it by each of 1, 2, and 3: # 192 × 1 = 192 # 192 × 2 = 384 # 192 × 3 = 576 # By concatenating each product we get the 1 to 9 pandigital, 192384576. We will call 192384576 the concatenated product of 192 and (1,2,3) # The same can be achieved by starting with 9 and multiplying by 1, 2, 3, 4, and 5, giving the pandigital, 918273645, which is the concatenated product of 9 and (1,2,3,4,5). # What is the largest 1 to 9 pandigital 9-digit number that can be formed as the concatenated product of an integer with (1,2, ... , n) where n > 1? # ### import itertools def is_palindrom(s): return len(s) == 9 and ''.join(sorted(s)) == '123456789' largest = 0 for n in range(1, 987654321): results = [] for mul in itertools.count(1): results.append(n * mul) str_res = ''.join([str(x) for x in results]) res = int(str_res) if is_palindrom(str_res) and res > largest: largest = res print(largest) if res > 987654321: break print(largest)