MathDB
Jump Around the Regular Hexagon

Source: 1997 National High School Mathematics League, Exam One, Problem 11

March 4, 2020

Problem Statement

ABCDEFABCDEF is a regular hexagon. A frog sarts jumping at AA, each time it can jump to one of the two adjacent points. If the frog jump to DD in no more than five times, it stops. After five jumpings, if the frog hasn't jumped to DD yet, it will stop as well. Then the number of different ways to jump is________.