Y by
Soma has a tower of
bricks , consisting of
levels. On the
-th level from the top, there are
bricks (where
), and every brick which is not on the lowest level lies on precisely
smaller bricks (which lie one level below) - see the figure. Soma takes away
bricks from the tower, one by one. He can only remove a brick if there is no brick lying on it. In how many ways can he do this, if the order of removals is considered as well?









This post has been edited 4 times. Last edited by parmenides51, Jan 7, 2022, 11:01 AM