Problem
COM-B1-M12-P014 Set 4. Dominoes
#14
★★★☆☆ Level 3 of 5
In how many ways can a \(2\times7\) board be tiled by dominoes?
Last column vertical or two horizontal dominoes.
For \(a_n\), \(a_n=a_{n-1}+a_{n-2}\), \(a_0=1\), \(a_1=1\). The values give \(a_7=21\).
Recurrence in a mock olympiad set.