Given a series 7, 15, 32, …… Find the nth term of this series.
Examples :
Input : 5 Output : 138 Input : 7 Output : 568
Approach: By seeing the pattern of the series we can easily identify that it is a mixed series.
S = 7, 15, 32…..
Each element in the series is multiplied by 2 and then incremented one more than the previous.
S = 7, 15 (2 * 7 + 1), 32 (2 * 15 + 2)…….
By using iteration we can easily find nth term of the series.
Below is the implementation of the above approach :
C++
// CPP program to find nth term #include <bits/stdc++.h> using namespace std;
// utility function int findTerm( int n)
{ if (n == 1)
return n;
else {
// since first element of the
// series is 7, we initialise
// a variable with 7
int term = 7;
// Using iteration to find nth
// term
for ( int i = 2; i <= n; i++)
term = term * 2 + (i - 1);
return term;
}
} // driver function int main()
{ int n = 5;
cout << findTerm(n);
return 0;
} |
Java
// Java program to find nth term import java.lang.*;
class GFG {
// utility function static int findTerm( int n)
{ if (n == 1 )
return n;
else {
// since first element of the
// series is 7, we initialise
// a variable with 7
int term = 7 ;
// Using iteration to find nth
// term
for ( int i = 2 ; i <= n; i++)
term = term * 2 + (i - 1 );
return term;
}
} // Driver code public static void main(String[] args)
{ int n = 5 ;
System.out.print(findTerm(n));
} } // This code is contributed by Anant Agarwal. |
Python3
# Python3 program to find nth term # utility function def findTerm(n) :
if n = = 1 :
return n
else :
# since first element of the
# series is 7, we initialise
# a variable with 7
term = 7
# Using iteration to find nth
# term
for i in range ( 2 , n + 1 ) :
term = term * 2 + (i - 1 );
return term;
# driver function print (findTerm( 5 ))
# This code is contributed by Saloni Gupta |
C#
// C# program to find nth term using System;
class GFG {
// utility function
static int findTerm( int n)
{
if (n == 1)
return n;
else {
// since first element of the
// series is 7, we initialise
// a variable with 7
int term = 7;
// Using iteration to find nth
// term
for ( int i = 2; i <= n; i++)
term = term * 2 + (i - 1);
return term;
}
}
// Driver code
public static void Main()
{
int n = 5;
Console.WriteLine(findTerm(n));
}
} // This code is contributed by vt_m. |
PHP
<?php // PHP program to find nth term // utility function function findTerm( $n )
{ if ( $n == 1)
return $n ;
else {
// since first element of the
// series is 7, we initialise
// a variable with 7
$term = 7;
// Using iteration to find nth
// term
for ( $i = 2; $i <= $n ; $i ++)
$term = $term * 2 + ( $i - 1);
return $term ;
}
} // Driver Code $n = 5;
echo (findTerm( $n ));
// This code is contributed by Ajit. ?> |
Javascript
<script> // Javascript program to find nth term // utility function function findTerm(n)
{ if (n == 1)
return n;
else {
// since first element of the
// series is 7, we initialise
// a variable with 7
let term = 7;
// Using iteration to find nth
// term
for (let i = 2; i <= n; i++)
term = term * 2 + (i - 1);
return term;
}
} // Driver Code let n = 5; document.write(findTerm(n)); // This code is contributed by gfgking. </script> |
Output
138
Time Complexity: O(n) since for loop will run for n times in worst case
Auxiliary Space: O(1)