Given a number N. The task is to write a program to find the Nth term in the below series:
0, 2, 4, 8, 12, 18…
Examples:
Input: 3 Output: 4 For N = 3 Nth term = ( 3 + ( 3 - 1 ) * 3 ) / 2 = 4 Input: 5 Output: 12
On observing carefully, the Nth term in the above series can be generalized as:
Nth term = ( N + ( N - 1 ) * N ) / 2
Below is the implementation of the above approach:
C++
// CPP program to find N-th term of the series: // 0, 2, 4, 8, 12, 18... #include <iostream> using namespace std;
// Calculate Nth term of series int nthTerm( int N)
{ return (N + N * (N - 1)) / 2;
} // Driver Function int main()
{ int N = 5;
cout << nthTerm(N);
return 0;
} |
Java
// Java program to find N-th term of the series: // 0, 2, 4, 8, 12, 18... import java.io.*;
// Main class for main method class GFG {
public static int nthTerm( int N)
{
// By using above formula
return (N + (N - 1 ) * N) / 2 ;
}
// Driver code
public static void main(String[] args)
{
int N = 5 ; // 5th term is 12
System.out.println(nthTerm(N));
}
} |
Python 3
# Python 3 program to find N-th term of the series: # 0, 2, 4, 8, 12, 18. # Calculate Nth term of series def nthTerm(N) :
return (N + N * (N - 1 )) / / 2
# Driver Code if __name__ = = "__main__" :
N = 5
print (nthTerm(N))
# This code is contributed by ANKITRAI1 |
C#
// C# program to find N-th term of the series: // 0, 2, 4, 8, 12, 18... using System;
class gfg
{ // Calculate Nth term of series
public int nthTerm( int N)
{
int n = ((N + N * (N - 1)) / 2);
return n;
}
//Driver program
static void Main( string [] args)
{
gfg p = new gfg();
int a = p.nthTerm(5);
Console.WriteLine(a);
Console.Read();
}
} //This code is contributed by SoumikMondal |
PHP
<?php // PHP program to find // N-th term of the series: // 0, 2, 4, 8, 12, 18... // Calculate Nth term of series function nthTerm( $N )
{ return (int)(( $N + $N *
( $N - 1)) / 2);
} // Driver Code $N = 5;
echo nthTerm( $N );
// This code is contributed by mits ?> |
Javascript
<script> // JavaScript program to find N-th term of the series: // 0, 2, 4, 8, 12, 18... // Calculate Nth term of series function nthTerm(N)
{ return parseInt((N + N * (N - 1)) / 2);
} // Driver Function let N = 5;
document.write(nthTerm(N));
// This code contributed by Rajput-Ji </script> |
Output:
12
Time Complexity: O(1)
Auxiliary space: O(1) as it is using constant variables
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