给定数字n,任务是找到第n个八面体数。
八面体数属于伪造数,它是由紧密堆积的球体构成的八面体中的球体数。前几个八面体数(其中n = 0、1、2、3…。)是:0、1、6、19,依此类推。
例子 :
Input : 4
Output : 44
Input : 8
Output : 344
第n个八面体数的公式:
n * (2n2+1) / 3
C++
// C++ program to find nth
// octahedral number
#include
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
Javascript
输出 :
5th Octahedral number: 85
参考:https://en.wikipedia.org/wiki/八面体编号