Given an integer N. The task is to write a program to find the Nth term of the given series:
2 + 6 + 13 + 23 + …
Examples:
Input : N = 5 Output : 36 Input : N = 10 Output : 146
Refer the article on How to find Nth term of series to know idea behind finding Nth term of any given series.
The generalized N-th term of given series is:
Below is the implementation of above approach:
C++
//CPP program to find Nth term of the series // 2 + 6 + 13 + 23 + 36 + ... #include<bits/stdc++.h> using namespace std;
// calculate Nth term of given series int Nth_Term( int n)
{ return (3 * pow (n, 2) - n + 2) / (2);
} // Driver code int main()
{ int N = 5;
cout<<Nth_Term(N)<<endl; } |
Java
//Java program to find Nth term of the series // 2 + 6 + 13 + 23 + 36 + ... import java.io.*;
class GFG {
// calculate Nth term of given series static int Nth_Term( int n)
{ return ( int )( 3 * Math.pow(n, 2 ) - n + 2 ) / ( 2 );
} // Driver code public static void main (String[] args) {
int N = 5 ;
System.out.println(Nth_Term(N));
}
} // This code is contributed by anuj_67.. |
Python3
# Python program to find Nth term of the series # 2 + 6 + 13 + 23 + 36 + ... # calculate Nth term of given series def Nth_Term(n):
return ( 3 * pow (n, 2 ) - n + 2 ) / / ( 2 )
# Driver code N = 5
print (Nth_Term(N))
|
C#
// C# program to find Nth term of the series // 2 + 6 + 13 + 23 + 36 + ... class GFG
{ // calculate Nth term of given series static int Nth_Term( int n)
{ return ( int )(3 * System.Math.Pow(n, 2) -
n + 2) / (2);
} // Driver code static void Main ()
{ int N = 5;
System.Console.WriteLine(Nth_Term(N));
} } // This code is contributed by mits |
PHP
<?php // PHP program to find // Nth term of the series // 2 + 6 + 13 + 23 + 36 + ... // calculate Nth term of given series function Nth_Term( $n )
{ return (3 * pow( $n , 2) - $n + 2) / (2);
} // Driver code $N = 5;
echo (Nth_Term( $N ));
// This code is contributed // by Sach_Code ?> |
Javascript
<script> // java script program to find // Nth term of the series // 2 + 6 + 13 + 23 + 36 + ... // calculate Nth term of given series function Nth_Term(n)
{ return (3 * Math.pow(n, 2) - n + 2) / (2);
} // Driver code let N = 5; document.write (Nth_Term(N)); // This code is contributed // by bobby </script> |
Output:
36
Time complexity: O(1), since there is no loop or recursion.
Auxiliary Space: O(1), since no extra space has been taken.