Probability

Hopscotch with a Two-Step Limit

Difficulty
A frog wants to hop from \( A(0,0) \) to \( B(7,4) \). Each hop is 1 unit right \( (R) \) or 1 unit up \( (U) \). The frog never hops in the same direction more than twice in a row. How many admissible hop-sequences exist?
Scratchpad