Program to find Nth term of series 1, 3, 12, 60, 360…

Given a number N. The task is to write a program to find the Nth term in the below series:

1, 3, 12, 60, 360…

Examples:

Input: 2
Output: 3

Input: 4
Output: 60

Approach: The idea is to first find the factorial of the number (N+1), that is (N+1)!



Now, the N-th term in the above series will be:

N-th term = (N+1)!/2

Below is the implementation of the above approach:

C++

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// CPP program to find N-th term of the series:
// 1, 3, 12, 60, 360…
  
#include <iostream>
using namespace std;
  
// Function to find factorial of N
int factorial(int N)
{
    int fact = 1;
  
    for (int i = 1; i <= N; i++)
        fact = fact * i;
  
    // return factorial of N+1
    return fact;
}
  
// calculate Nth term of series
int nthTerm(int N)
{
    return (factorial(N + 1) / 2);
}
  
// Driver Function
int main()
{
  
    // Taking n as 6
    int N = 6;
  
    // Printing the nth term
    cout << nthTerm(N);
  
    return 0;
}

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Java

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// Java program to find N-th
// term of the series:
// 1, 3, 12, 60, 360
  
import java.util.*;
import java.lang.*;
import java.io.*;
  
class GFG {
  
    // Function to find factorial of N
    static int factorial(int N)
    {
        int fact = 1;
  
        for (int i = 1; i <= N; i++)
            fact = fact * i;
  
        // return factorial of N
        return fact;
    }
  
    // calculate Nth term of series
    static int nthTerm(int N)
    {
        return (factorial(N + 1) / 2);
    }
  
    // Driver Code
    public static void main(String args[])
    {
  
        // Taking  n as 6
        int N = 6;
  
        // Printing the nth term
        System.out.println(nthTerm(N));
    }
}

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Python3

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# Python 3 program to find 
# N-th term of the series: 
# 1, 3, 12, 60, 360… 
  
# Function for finding 
# factorial of N 
def factorial(N) : 
    fact = 1
    for i in range(1, N + 1) : 
        fact = fact *
  
    # return factorial of N 
    return fact 
  
# Function for calculating 
# Nth term of series 
def nthTerm(N) : 
  
    # return nth term 
    return (factorial(N + 1) // 2
  
# Driver code 
if __name__ == "__main__"
      
    N = 6
  
    # Function Calling 
    print(nthTerm(N)) 

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C#

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// C# program to find N-th 
// term of the series: 
// 1, 3, 12, 60, 360 
using System;
  
class GFG
{
      
// Function to find factorial of N 
static int factorial(int N) 
    int fact = 1; 
  
    for (int i = 1; i <= N; i++) 
        fact = fact * i; 
  
    // return factorial of N 
    return fact; 
  
// calculate Nth term of series 
static int nthTerm(int N) 
    return (factorial(N + 1) / 2); 
  
// Driver Code
static void Main()
{
    int N = 6 ;
      
    // Printing the nth term
    Console.WriteLine(nthTerm(N));
}
}
  
// This code is contributed
// by ANKITRAI1

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PHP

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<?php
// PHP program to find N-th term
// of the series: 1, 3, 12, 60, 360…
  
// Function to find factorial of N
function factorial($N)
{
    $fact = 1;
  
    for ($i = 1; $i <= $N; $i++)
        $fact = $fact * $i;
  
    // return factorial of N+1
    return $fact;
}
  
// calculate Nth term of series
function nthTerm($N)
{
    return (factorial($N + 1) / 2);
}
  
// Driver Code
  
// Taking n as 6
$N = 6;
  
// Printing the nth term
echo nthTerm($N);
  
// This code is contributed 
// by chandan_jnu..
?>

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Output:

2520


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