請教一題排列組合問題，謝謝。

n{ 0, 0, 0, 5 } = 1
n{ 0, 0, 1, 4 } = C(5,1) = 5
n{ 0, 0, 2, 3 } = C(5,2) = 10
n{ 0, 1, 1, 3 } = C(5,3) = 10
n{ 0, 1, 2, 2 } = C(5,1)* C(4,2)/2! = 15
n{ 1, 1, 1, 2 } = C(5,2) = 10
以上共 51 種