Encuentra el término N de la serie 1, 8, 54, 384…

Dado un número N. La tarea es escribir un programa para encontrar el N-ésimo término en la siguiente serie: 
 

1, 8, 54, 384...

Ejemplos: 
 

Input : 3
Output : 54
For N = 3
Nth term = ( 3*3) * 3!
         = 54

Input : 2 
Output : 8

Observando detenidamente, el término N de la serie anterior se puede generalizar como: 
 

Nth term = ( N*N ) * ( N! )

A continuación se muestra la implementación del enfoque anterior:
 

// CPP program to find N-th term of the series:
// 1, 8, 54, 384...
#include <iostream>
using namespace std;
 
// calculate factorial of N
int fact(int N)
{
    int i, product = 1;
    for (i = 1; i <= N; i++)
        product = product * i;
    return product;
}
 
// calculate Nth term of series
int nthTerm(int N)
{
    return (N * N) * fact(N);
}
 
// Driver Function
int main()
{
    int N = 4;
 
    cout << nthTerm(N);
 
    return 0;
}

// Java program to find N-th term of the series:
// 1, 8, 54, 384...
 
import java.io.*;
 
// Main class for main method
class GFG {
    public static int fact(int N)
    {
        int i, product = 1;
        // Calculate factorial of N
        for (i = 1; i <= N; i++)
            product = product * i;
        return product;
    }
    public static int nthTerm(int N)
    {
        // By using above formula
        return (N * N) * fact(N);
    }
 
    public static void main(String[] args)
    {
        int N = 4; // 4th term is 384
 
        System.out.println(nthTerm(N));
    }
}

# Python 3 program to find
# N-th term of the series:
# 1, 8, 54, 384...
 
# calculate factorial of N
def fact(N):
     
    product = 1
    for i in range(1, N + 1):
        product = product * i
    return product
 
# calculate Nth term of series
def nthTerm(N):
    return (N * N) * fact(N)
 
# Driver Code
if __name__ =="__main__":
    N = 4
    print(nthTerm(N))
 
# This code is contributed
# by ChitraNayal

// C# program to find N-th
// term of the series:
// 1, 8, 54, 384...
using System;
 
class GFG
{
public static int fact(int N)
{
    int i, product = 1;
     
    // Calculate factorial of N
    for (i = 1; i <= N; i++)
        product = product * i;
    return product;
}
 
public static int nthTerm(int N)
{
    // By using above formula
    return (N * N) * fact(N);
}
 
// Driver Code
public static void Main(String[] args)
{
    int N = 4; // 4th term is 384
 
    Console.WriteLine(nthTerm(N));
}
}
 
// This code is contributed
// by Kirti_Mangal

<?php
// PHP program to find N-th
/// term of the series:
// 1, 8, 54, 384...
 
// calculate factorial of N
function fact($N)
{
    $product = 1;
    for ($i = 1; $i <= $N; $i++)
        $product = $product * $i;
    return $product;
}
 
// calculate Nth term of series
function nthTerm($N)
{
    return ($N * $N) * fact($N);
}
 
// Driver Code
$N = 4;
 
echo nthTerm($N);
 
// This code is contributed
// by ChitraNayal
?>

<script>
 
// JavaScript program to find N-th term of the series:
// 1, 8, 54, 384...
 
// calculate factorial of N
function fact( N)
{
    let i, product = 1;
    for (i = 1; i <= N; i++)
        product = product * i;
    return product;
}
 
// calculate Nth term of series
function nthTerm( N)
{
    return (N * N) * fact(N);
}
 
// Driver Function
 
    let N = 4;
    document.write(nthTerm(N));
     
// This code contributed by Rajput-Ji
 
</script>

384

Complejidad de tiempo: O(N)

Complejidad espacial : O (1) porque usa variables constantes