# Pandigital multiples

*Author: Andrei Osipov*

https://projecteuler.net/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?

Source code: prob038-andreoss.pl

use v6; sub concat-product($x, $n) { + [~] do for 1...$n { $x * $_ } } sub is-pandigital(Int $n is copy) { return unless 123456789 <= $n <= 987654321; my $x = 0; loop ( ; $n != 0 ; $n div=10) { my $d = $n mod 10; $x += $d * 10 ** (9 - $d); } $x == 123456789; } say max gather for 1 .. 9999 -> $x { next if $x !~~ /^^9/; for 2 .. 5 -> $n { my $l = concat-product $x, $n; take $l if is-pandigital $l; } }