Given a number N, the task is to find the Nth term of this series:
3, 5, 21, 51, 95, ….
Examples:
Input: N = 4 Output: 51 Explanation: Nth term = (7 * pow(N, 2) - 19 * N + 15) = (7 * pow(4, 2) - 19 * 4 + 15) = 51 Input: N = 10 Output: 525
Approach:
The Nth term of the given series can be generalized as:
[Tex] [/Tex]
Below is the implementation of the above approach:
C++
// CPP program to find N-th term of the series: // 3, 5, 21, 51, 95,... #include <iostream> #include <math.h> using namespace std;
// calculate Nth term of series int getNthTerm( long long int N)
{ // Return Nth term
return (7 * pow (N, 2) - 19 * N + 15);
} // driver code int main()
{ // declaration of number of terms
long long int N = 4;
// Get the Nth term
cout << getNthTerm(N);
return 0;
} |
Java
// Java program to find N-th term of the series: // 3, 5, 21, 51, 95,... import java.util.*;
class solution
{ static long getNthTerm( long N)
{ // Return Nth term return ( 7 *( int ) Math.pow(N, 2 ) - 19 * N + 15 );
} //Driver program public static void main(String arr[])
{ // declaration of number of terms long N = 4 ;
// Get the Nth term
System.out.println(getNthTerm(N));
} } |
Python3
# Python3 program to find N-th term # of the series: # 3, 5, 21, 51, 95,... # calculate Nth term of series def getNthTerm(N):
#Return Nth term
return ( 7 * pow (N, 2 ) - 19 * N + 15 )
#Driver code if __name__ = = '__main__' :
#declaration of number of terms N = 4
#Get the Nth term print (getNthTerm(N))
#this code is contributed by Shashank_Sharma |
C#
// C# program to find // N-th term of the series: // 3, 5, 21, 51, 95,... using System;
class GFG
{ static long getNthTerm( long N)
{ // Return Nth term
return (7 *( int ) Math.Pow(N, 2) -
19 * N + 15);
} // Driver Code static public void Main ()
{ // declaration of number
// of terms
long N = 4;
// Get the Nth term
Console.Write(getNthTerm(N));
} } // This code is contributed by Raj |
PHP
<?php // PHP program to find // N-th term of the series: // 3, 5, 21, 51, 95,... // calculate Nth term of series function getNthTerm( $N )
{ // Return Nth term
return (7 * pow( $N , 2) -
19 * $N + 15);
} // Driver code // declaration of number // of terms $N = 4;
// Get the Nth term echo getNthTerm( $N );
// This code is contributed // by anuj_67 ?> |
Javascript
<script> // JavaScript program to find N-th term of the series: // 3, 5, 21, 51, 95,... // calculate Nth term of series function getNthTerm(N)
{ // Return Nth term
return (7 * Math.pow(N, 2) - 19 * N + 15);
} // driver code // declaration of number of terms
let N = 4;
document.write( getNthTerm(N) );
// This code contributed by gauravrajput1 </script> |
Output:
51
Time Complexity: O(1)
Auxiliary Space : O(1) since using constant variables