Find Nth term of the series 1, 6, 18, 40, 75, ….
Given a number n, the task is to find the n-th term in series 1, 6, 18, 40, 75, …
Example:
Input: N = 2 Output: 6 Explanation: 2nd term = (2^2*(2+1))/2 = 6 Input: N = 5 Output: 75 Explanation: 5th term = (5^2*(5+1))/2 = 75
Approach:
Nth term = (N^2*(N+1))/2
Implementation of the above approach is given below:
C++
// CPP code to generate // 'Nth' term of this sequence #include <bits/stdc++.h> using namespace std; // Function to generate a fixed number int nthTerm( int N) { int nth = 0; //(N^2*(N+1))/2 nth = (N * N * (N + 1)) / 2; return nth; } // Driver Method int main() { int N = 5; cout << nthTerm(N) << endl; return 0; } |
Java
// Java code to generate // 'Nth' term of this sequence class GFG { // Function to generate a fixed number public static int nthTerm( int N) { int nth = 0 ; //(N^2*(N+1))/2 nth = (N * N * (N + 1 )) / 2 ; return nth; } // Driver Method public static void main(String[] args) { int N = 5 ; System.out.println(nthTerm(N)); } // This code is contributed by 29AjayKumar } |
Python3
# python program to find out'Nth' term of this sequence # Function to generate a fixed number def nthTerm(N): nth = 0 nth = (N * N * (N + 1 )) / / 2 return nth # Driver code N = 5 print (nthTerm(N)) # This code is contributed by Shrikant13 |
C#
// C# code to generate // 'Nth' term of this sequence using System; public class GFG { // Function to generate a fixed number public static int nthTerm( int N) { int nth = 0; //(N^2*(N+1))/2 nth = (N * N * (N + 1)) / 2; return nth; } // Driver Method public static void Main( string [] args) { int N = 5; Console.WriteLine(nthTerm(N)); } } // This code is contributed by Shrikant13 |
PHP
<?php // PHP code to generate // 'Nth' term of this sequence // Function to generate a fixed number function nthTerm( $N ) { $nth = 0; // (N^2*(N+1))/2 $nth = ( $N * $N * ( $N + 1)) / 2; return $nth ; } // Driver Code $N = 5; echo nthTerm( $N ); // This code is contributed // by chandan_jnu ?> |
Javascript
<script> // Javascript code to generate // 'Nth' term of this sequence // Function to generate a fixed number function nthTerm(N) { let nth = 0; //(N^2*(N+1))/2 nth = parseInt((N * N * (N + 1)) / 2); return nth; } // Driver Method let N = 5; document.write(nthTerm(N)); // This code is contributed by subham348. </script> |
Output:
75
Time Complexity: O(1)
Auxiliary Space: O(1)