Program to find Nth term of the series 3 , 5 , 21 , 51 , 95 , …
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
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