A (one-sided) marked domino is a piece consisting of two squares joined along an edge, where each square on one side of the piece is marked with 0, 1, 2, 3, 4, 5, or 6 dots. The two squares of a marked domino may receive the same number of dots.
(a) Use Theorem 14.2.3 to determine the number of different marked dominoes.
(b) How many different marked dominoes are there if we are allowed to mark the squares with 0, 1, ..., p - 1, or p dots?