Given a number N. The task is to write a program to find the Nth term in the below series:
1, 8, 54, 384...
Examples:
Input : 3 Output : 54 For N = 3 Nth term = ( 3*3) * 3! = 54 Input : 2 Output : 8
On observing carefully, the Nth term in the above series can be generalized as:
Nth term = ( N*N ) * ( N! )
Below is the implementation of the above approach:
C++
// 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
// 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
# 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#
// 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 // 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 ?> |
Javascript
<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
Time Complexity: O(N)
Space Complexity: O(1) because using constant variables
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