Question 8
Alex makes strings from striped and plain beads. Start with a striped bead followed by a plain bead.
At each step choose either (i) add one plain bead to each end, or (ii) append two striped beads to the right end. These steps may be repeated.
How many of the following four strings can Alex create?
At each step choose either (i) add one plain bead to each end, or (ii) append two striped beads to the right end. These steps may be repeated.
How many of the following four strings can Alex create?