C :

#include<stdio.h>

int main()
{
	int i,c,n,a[31],b[31],sum;
	a[1]=1;
	sum=a[1];
	for(i=2;i<=30;i++)
	{
		if(i%2==0)
		{
			a[i]=sum+2;
			sum=sum+a[i];
		}
		else
		{
			a[i]=sum+1;
			sum=sum+a[i];
		}
	}
	scanf("%d",&c);
	while(c--)
	{
		scanf("%d",&n);
		printf("%d\n",a[n]);
	}
	return 0;
}

C++ :

#include<stdio.h>

int main()
{
	int i,c,n,a[31],b[31],sum;
	a[1]=1;
	sum=a[1];
	for(i=2;i<=30;i++)
	{
		if(i%2==0)
		{
			a[i]=sum+2;
			sum=sum+a[i];
		}
		else
		{
			a[i]=sum+1;
			sum=sum+a[i];
		}
	}
	scanf("%d",&c);
	while(c--)
	{
		scanf("%d",&n);
		printf("%d\n",a[n]);
	}
	return 0;
}

Pascal :

program floor;
var i,n,c:longint;
    a:array[1..30] of longint;
begin
    a[1]:=1;
    a[2]:=3;
    for i:=3 to 30 do
      a[i]:=a[i-1]+2*a[i-2];
    readln(c);
    for i:=1 to c do
      begin
        readln(n);
        writeln(a[n]);
      end;
end.

Java :

import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		 int a=sc.nextInt();
		 int[] b=new int[31];
		 b[1]=1;
		 b[2]=3;
		 for(int i=3;i<31;i++){
			  b[i]=b[i-1]+2*b[i-2];  
		  }
		while(a--!=0){
		  System.out.println(b[sc.nextInt()]);
		}
	}
}