Math POW , 0000-9999 4 digit number in ascending order including 0 in the front?

There are 13 combinations as you can have 1234, 2345,3456, 4567, 5678, and 6789, then there's, 9876, 8765, 7654, 6543, 5432, 4321, and 3210, hope this helps, everyone else has forgotten the opposite way ha! ha! ha!