Question 24
(MON 1) Find the number of all $n$-digit numbers for which some fixed digit stands only in the $i$th $(1\lt i\lt n)$ place and the last $j$ digits are distinct.
Source footnote 3. The problem is unclear. Presumably $n,i,j$ and the $i$th digit are fixed.
Source footnote 3. The problem is unclear. Presumably $n,i,j$ and the $i$th digit are fixed.