Java Program For Number Series

If I enter number 5 then output should be as below.

Output = 5*5 - 4*4 + 3*3 - 2*2 + 1*1

If I enter 4 then

Output = 4*4 - 3*3 + 2*2 - 1*1

Below is code.

First Method : 

public class JavaExampleSeries 
{
 
 public static void main(String[] args)
 {
  int number = 5;
  long output = 0;
  int counter = 1;  
  
  if(number%2==0)
  {
   for(int i=number; i>=1; i--)
   {
    if(counter%2==0)
    {
     output = output - i*i;
    }
    else
    {
     output = output + i*i;
    }
    counter++;
   }
  }
  else
  {
   for(int i=number; i>1; i--)
   {
    if(counter%2==0)
    {
     output = output - i*i;
    }
    else
    {
     output = output + i*i;
    }
    counter++;
   }
   output = output+1;
  }
  
  System.out.println("Output is : " + output);
 }
 
}

Second Method :

public class JavaExampleSeries 
{
 
 public static void main(String[] args)
 {
  int number = 5;
  long output = 0;         
  int iterations = number/2;
  
  for(int i=1; i<=iterations; i++)
  {
   output = output + ((number*number)-((number-1)*(number-1)));
   
   number = number-2;   
  }
  
  if(number%2>0)
  {
   output = output+1;
  }
    
  System.out.println("Output is : " + output);  
 } 
}