We say that some positive integer m covers the number 1998, if 1,9,9,8 appear in this order as digits of m. (For instance 1998 is covered by 2<spanclass=′latex−bold′>1</span>59<spanclass=′latex−bold′>9</span>36<spanclass=′latex−bold′>98</span> but not by 213326798.) Let k(n) be the number of positive integers that cover 1998 and have exactly n digits (n≥5), all different from 0. What is the remainder of k(n) on division by 8? combinatorics proposedcombinatorics