5. Palindromes are compositions of numbers that read the same left to right as right to left. For example, 3 and 1 + 1 + 1 are palindromes of 3, and the palindromes of 4 are 4, 1 + 2 + 1, 2 + 2, 1+1+1+1. Let Pn denote the number of palindromes of n. (a) Explain why the recursive formula for Pn is Pn = 2Pn-2, for n 2 3. (The start values are P1 = 1 and P2 = 2. ) (b) Find a closed form for Pn. (c) Using the closed form, calculate the number of palindromes of 10