Find the Nth term of the series 14, 28, 20, 40,…..

Given a number N. The task is to find the N-th term in the following series:

14, 28, 20, 40, 32, 64…..

Examples:

Input : N = 5
Output : 32

Input : N = 6
Output : 64

Approach:

  1. Initialize first number with 14.
  2. Run a loop from i = 2 to N and do following steps:
    • For Even i, double the previous term. For example if i = 2, current term will be 2*(term when i = 1), that is 2*14 = 28.
    • For Odd i, subtract 8 from the previous term.
    • Exit the loop and print the final number.

Below is the implementation of the above approach:

C++

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// CPP program to find the Nth term of
// the series 14, 28, 20, 40, …..
  
#include <iostream>
using namespace std;
  
// Function to find the N-th term
int findNth(int N)
{
    // initializing the 1st number
    int b = 14;
  
    int i;
  
    // loop from 2nd term to nth term
    for (i = 2; i <= N; i++) {
        // if i is even, double the
        // previous number
        if (i % 2 == 0)
            b = b * 2;
        // if i is odd, subtract 8 from
        // previous number
        else
            b = b - 8;
    }
  
    return b;
}
  
// Driver Code
int main()
{
    int N = 6;
  
    cout << findNth(N);
  
    return 0;
}

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Java

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// Java program to find the Nth term of
// the series 14, 28, 20, 40,
  
import java.io.*;
  
class GFG {
    
  
// Function to find the N-th term
 static int findNth(int N)
{
    // initializing the 1st number
    int b = 14;
  
    int i;
  
    // loop from 2nd term to nth term
    for (i = 2; i <= N; i++) {
        // if i is even, double the
        // previous number
        if (i % 2 == 0)
            b = b * 2;
        // if i is odd, subtract 8 from
        // previous number
        else
            b = b - 8;
    }
  
    return b;
}
  
// Driver Code
  
  
    public static void main (String[] args) {
        int N = 6;
  
    System.out.print(findNth(N));
    }
}
// This code is contributed by shs

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Python 3

# Python 3 program to find the Nth term
# of the series 14, 28, 20, 40, …..

# Function to find the N-th term
def findNth(N):

# initializing the 1st number
b = 14

# loop from 2nd term to nth term
for i in range (2, N + 1):

# if i is even, double the
# previous number
if (i % 2 == 0):
b = b * 2

# if i is odd, subtract 8 from
# previous number
else:
b = b – 8

return b

# Driver Code
N = 6

print(findNth(N))

# This code is contributed
# by Akanksha Rai

C#

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// C# program to find the Nth term of
// the series 14, 28, 20, 40,
  
using System;
  
public class GFG{
    // Function to find the N-th term
static int findNth(int N)
{
    // initializing the 1st number
    int b = 14;
  
    int i;
  
    // loop from 2nd term to nth term
    for (i = 2; i <= N; i++) {
        // if i is even, double the
        // previous number
        if (i % 2 == 0)
            b = b * 2;
        // if i is odd, subtract 8 from
        // previous number
        else
            b = b - 8;
    }
  
    return b;
}
  
// Driver Code
      
    static public void Main (){
    int N = 6;
    Console.WriteLine(findNth(N));
    }
}
// This code is contributed by ajit

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PHP

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<?php
// PHP program to find the Nth term of
// the series 14, 28, 20, 40, …..
  
// Function to find the N-th term
function findNth($N)
{
    // initializing the 1st number
    $b = 14;
  
    // loop from 2nd term to nth term
    for ($i = 2; $i <= $N; $i++) 
    {
        // if i is even, double the
        // previous number
        if ($i % 2 == 0)
            $b = $b * 2;
              
        // if i is odd, subtract 8 from
        // previous number
        else
            $b = $b - 8;
    }
    return $b;
}
  
// Driver Code
$N = 6;
echo findNth($N);
  
// This code is contributed by akt_mit
?>

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Output:

64


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Improved By : Shashank12, jit_t, Akanksha_Rai