APMC 1998
Source:
June 4, 2011
combinatorics unsolvedcombinatorics
Problem Statement
For n points in that order on a straight line. We colored each point by 1 in 5 white, red, green, blue, and purple. A coloring is called acceptable if two consecutive points is the same color or 2 points with at least one of 2 points are colored white. How many ways acceptable color?