x+y+z=3n,
若n=1,则3个数字为0,1,2,三数的排列共p(3,3)=6.
若n=2,则3个数字为0,1,5,4,2,0,3,2,1,总共排列共3p(3,3)=18.
若n=3,则3个数字为8,1,0,7,2,0,6,3,0,6,2,1,5,4,0,5,3,1,4,3,2,排列共7p(3,3)=42.
若n=4,则3个数字为9,0,3,9,2,1,8,0,4,8,1,3,7,0,5,7,4,1,7,3,2,6,5,1,6,4,2,5,4,3,排列共10p(3,3)=60.
若n=5,则3个数字为9,6,0,9,5,1,9,4,2,8,7,0,8,6,1,8,5,2,8,4,3,7,6,2,7,5,3,6,5,4,排列共10p(3,3)=60.
若n=6,则3个数字为9,8,1,9,7,2,9,6,3,9,5,4,8,7,3,8,6,4,7,6,5,排列共7p(3,3)=42.
若n=7,则3个数字为9,8,4,9,7,5,8,7,6,总共排列共3p(3,3)=18.
若n=8,则3个数字为9,8,7,排列共p(3,3)=6.
总计：252