Given a integer h, find the possible number of balanced binary trees of height h.

// Java program to count number of balanced  
// binary trees of height h.  
class GFG { 
      
    static final int MOD = 1000000007; 
      
    public static long countBT(int h) { 
        long[] dp = new long[h + 1]; 
          
        // base cases 
        dp[0] = 1; 
        dp[1] = 1; 
          
        for(int i = 2; i <= h; ++i)  
            dp[i] = (dp[i - 1] * ((2 * dp [i - 2])% MOD + dp[i - 1]) % MOD) % MOD; 
              
            return dp[h]; 
    } 
      
    // Driver program 
    public static void main (String[] args) { 
        int h = 3;  
        System.out.println("No. of balanced binary trees of height "+h+" is: "+countBT(h));  
    } 
} 
/* 
This code is contributed by 
Brij Raj Kishore 
*/