Given a number n, the task is to find n-th octahedral number.
An octahedral number belongs to a figurate number and it is the number of spheres in an octahedron built from closely packed spheres. First, a few octahedral numbers (where n = 0, 1, 2, 3…….) are 0, 1, 6, 19, and so on.
Examples :
Input: 4
Output: 44Input: 8
Output: 344
n * (2n2+1) / 3
C++
// C++ program to find nth // octahedral number #include <bits/stdc++.h> using namespace std;
// Function to find // octahedral number int octahedral_num( int n)
{ // Formula to calculate nth
// octahedral number
return n * (2 * n * n + 1) / 3;
} // Drivers code int main()
{ int n = 5;
// print result
cout << n << "th Octahedral number: " ;
cout << octahedral_num(n);
return 0;
} |
Java
// Java program to find nth octahedral // number import java.io.*;
class GFG {
// Function to find octahedral number
static int octahedral_num( int n)
{
// Formula to calculate nth
// octahedral number
// and return it into main function.
return n * ( 2 * n * n + 1 ) / 3 ;
}
// Driver Code
public static void main(String[] args)
{
int n = 5 ;
// print result
System.out.print(n + "th Octahedral"
+ " number: " );
System.out.println(octahedral_num(n));
}
} |
Python3
# Python 3 program to find nth # octahedral number # Function to find # octahedral number def octahedral_num(n) :
# Formula to calculate nth
# octahedral number
return n * ( 2 * n * n + 1 ) / / 3
# Driver Code if __name__ = = '__main__' :
n = 5
print (n, "th Octahedral number: "
, octahedral_num(n))
# This code is contributed ajit. |
C#
// C# program to find nth // Octahedral number using System;
class GFG
{ // Function to find
// octahedral number
static int octahedral_num( int n)
{
// Formula to calculate
// nth octahedral number
// and return it into
// main function.
return n * (2 * n *
n + 1) / 3;
}
// Driver Code
static public void Main ()
{
int n = 5;
// print result
Console.Write(n + "th Octahedral"
+ " number: " );
Console.WriteLine(octahedral_num(n));
}
} // This code is Contributed by m_kit |
PHP
<?php // PHP program to find nth // octahedral number // Function to find // octahedral number function octahedral_num( $n )
{ // Formula to calculate nth
// octahedral number
// and return it into main function.
return $n * (2 * $n * $n + 1) / 3;
} // Drivers Code $n = 5;
// print result echo $n , "th Octahedral number: " ;
echo octahedral_num( $n );
?> |
Javascript
<script> // JavaScript program to find nth // octahedral number // Function to find // octahedral number function octahedral_num( n)
{ // Formula to calculate nth
// octahedral number
// and return it into main function.
return n * (2 * n * n + 1) / 3;
} // Drivers Code let n = 5; // print result document.write( n+ "th Octahedral number: " );
document.write(octahedral_num(n)); // This code is contributed by Bobby </script> |
Output
5th Octahedral number: 85
Time Complexity: O(1) because constant operations are being performed
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Octahedral_number
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