Given a number N, the task is to find Nth Enneacontagon number.
A Enneacontagon number. is class of figurate number. It has 90 – sided polygon called enneacontagon. The N-th enneacontagon number count’s the 90 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few enneacontagonol numbers are 1, 90, 267, 532 …
Examples:
Input: N = 2
Output: 90
Explanation:
The second enneacontagonol number is 90.
Input: N = 3
Output: 267
Approach: The N-th enneacontagon number is given by the formula:
- Nth term of s sided polygon =
- Therefore Nth term of 90 sided polygon is
Below is the implementation of the above approach:
// C++ program for above approach #include <bits/stdc++.h> using namespace std;
// Finding the nth enneacontagon Number int enneacontagonNum( int n)
{ return (88 * n * n - 86 * n) / 2;
} // Driver Code int main()
{ int n = 3;
cout << "3rd enneacontagon Number is = "
<< enneacontagonNum(n);
return 0;
} // This code is contributed by Akanksha_Rai |
// C program for above approach #include <stdio.h> #include <stdlib.h> // Finding the nth enneacontagon Number int enneacontagonNum( int n)
{ return (88 * n * n - 86 * n) / 2;
} // Driver program to test above function int main()
{ int n = 3;
printf ( "3rd enneacontagon Number is = %d" ,
enneacontagonNum(n));
return 0;
} |
// Java program for above approach class GFG{
// Finding the nth enneacontagon number public static int enneacontagonNum( int n)
{ return ( 88 * n * n - 86 * n) / 2 ;
} // Driver code public static void main(String[] args)
{ int n = 3 ;
System.out.println( "3rd enneacontagon Number is = " +
enneacontagonNum(n));
} } // This code is contributed by divyeshrabadiya07 |
# Python3 program for above approach # Finding the nth enneacontagon Number def enneacontagonNum(n):
return ( 88 * n * n - 86 * n) / / 2
# Driver Code n = 3
print ( "3rd enneacontagon Number is = " ,
enneacontagonNum(n))
# This code is contributed by divyamohan123 |
// C# program for above approach using System;
class GFG{
// Finding the nth enneacontagon number public static int enneacontagonNum( int n)
{ return (88 * n * n - 86 * n) / 2;
} // Driver code public static void Main(String[] args)
{ int n = 3;
Console.WriteLine( "3rd enneacontagon Number is = " +
enneacontagonNum(n));
} } // This code is contributed by Rajput-Ji |
<script> // JavaScript program for above approach // Finding the nth enneacontagon Number function enneacontagonNum(n)
{ return (88 * n * n - 86 * n) / 2;
} // Driver Code var n = 3;
document.write( "3rd enneacontagon Number is = " + enneacontagonNum(n));
</script> |
Output:
3rd enneacontagon Number is = 267
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Enneacontagon