Let f(n) be a function satisfying the following three conditions for all positive integers n :
(a) f(n) is a positive integer,
(b) f(n+1)>f(n),
(c) f(f(n))=3 n.
Find f(2001).
Let f(n) be a function satisfying the following three conditions for all positive integers n :
(a) f(n) is a positive integer,
(b) f(n+1)>f(n),
(c) f(f(n))=3 n.
Find f(2001).