Skip to content

Domino tilings of a three by eight board

Question

In how many ways can a board of 33 rows and 88 columns be completely covered by non-overlapping dominoes, each covering two adjacent cells (horizontal or vertical)?

Short answer

153153. Let tnt_n count tilings of a 3×n3\times n board and sns_n tilings with one corner cell removed. Looking at the leftmost column gives tn=tn−2+2sn−1t_n=t_{n-2}+2s_{n-1} and sn=tn−1+sn−2s_n=t_{n-1}+s_{n-2}, which combine to tn=4tn−2−tn−4t_n=4t_{n-2}-t_{n-4}. Starting from t0=1,t2=3t_0=1,t_2=3 this gives 11,41,15311, 41, 153.

Adapted from QuantQuestions.io; question and answer rewritten by SelfMadeQuant.com.

See the hint and the full worked solution in the question bank (free account).

Open the worked solution

Lessons behind this question

Start with a free lesson: Probability Fundamentals is part of a free topic. Create a free account, no card needed, to read it in full with worked solutions.

Read it free