Dominos domino: 名 #of tilings 2 n an an-1 an-2 a0=1a1=1 Case.I 0… 2×(n-1) Case.2 2x(n-2) Dominos domino: 1 2 ￾ 2 n # of tilings Case.1 Case.2 2×(n-1) 2×(n-2) an = an￾1 + an￾2 a0 = 1 a1 = 1