AVL tree minimum node

Question

What is the minimum number of nodes in an AVL tree of height h? I did some reseach on the Internet but they are all so confusing.

Answer 1

n(h) be the minimum number of nodes of an AVL tree of height h, then:

n(0)=1, n(1)=2
n(h)= 1+n(h-1)+n(h-2)