八角号
给你一个数字 n，任务是找到 n 第个八角数。另外，找到八角系列直到 n. 一个八角数字是代表八角的数字。八边形数字可以通过在正方形的四个边上放置三角形数字来形成。八角数采用公式(3n2–2n)计算。 示例:
Input : 5
Output : 65
Input : 10
Output : 280
Input : 15
Output : 645
C++
// C++ program to find
// nth octagonal number
#include <bits/stdc++.h>
using namespace std;
// Function to calculate
//octagonal number
int octagonal(int n)
{
// Formula for finding
// nth octagonal number
return 3 * n * n - 2 * n;
}
// Driver function
int main()
{
int n = 10;
cout << n << "th octagonal number :"
<< octagonal(n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find
// nth octagonal number
import java.util.*;
import java.lang.*;
public class GfG {
// Function to calculate
//octagonal number
public static int octagonal(int n)
{
// Formula for finding
// nth octagonal number
return 3 * n * n - 2 * n;
}
// Driver function
public static void main(String argc[])
{
int n = 10;
System.out.println(n + "th octagonal" +
" number :" + octagonal(n));
}
}
/* This code is contributed by Sagar Shukla */
计算机编程语言
# Python program to find
# nth octagonal number
def octagonal(n):
return 3 * n * n - 2 * n
# Driver code
n = 10
print(n, "th octagonal number :",
octagonal(n))
C
// C# program to find nth octagonal number
using System;
public class GfG {
// Function to calculate
//octagonal number
public static int octagonal(int n)
{
// Formula for finding
// nth octagonal number
return 3 * n * n - 2 * n;
}
// Driver function
public static void Main()
{
int n = 10;
Console.WriteLine(n + "th octagonal"
+ " number :" + octagonal(n));
}
}
/* This code is contributed by Vt_m */
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to find
// nth octagonal number
// Function to calculate
//octagonal number
function octagonal($n)
{
// Formula for finding
// nth octagonal number
return 3 * $n * $n - 2 * $n;
}
// Driver Code
$n = 10;
echo $n , "th octagonal number :"
, octagonal($n);
// This code is contributed by Vt_m .
?>
java 描述语言
<script>
// JavaScript program to convert
// Binary code to Gray code
// Function to calculate
//octagonal number
function octagonal(n)
{
// Formula for finding
// nth octagonal number
return 3 * n * n - 2 * n;
}
// Driver code
let n = 10;
document.write(n + "th octagonal" +
" number :" + octagonal(n));
// This code is contributed by code_hunt.
</script>
输出:
10th octagonal number : 280
时间复杂度:O(1) T3】辅助空间: O(1)
给定 n，求八角级数直到 n。
我们还可以找到八角系列。八角系列包含八角上的点。
Octagonal series 1, 8, 21, 40, 65, 96, 133, 176, 225, 280, . . .
C++
// C++ program to display the
// octagonal series
#include <bits/stdc++.h>
using namespace std;
// Function to display
// octagonal series
void octagonalSeries(int n)
{
// Formula for finding
//nth octagonal number
for (int i = 1; i <= n; i++)
// Formula for computing
// octagonal number
cout << (3 * i * i - 2 * i);
}
// Driver function
int main()
{
int n = 10;
octagonalSeries(n);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find
// nth octagonal number
import java.util.*;
import java.lang.*;
public class GfG {
// Function to display octagonal series
public static void octagonalSeries(int n)
{
// Formula for finding
//nth octagonal number
for (int i = 1; i <= n; i++)
// Formula for computing
// octagonal number
System.out.print(3 * i * i - 2 * i);
}
// Driver function
public static void main(String argc[])
{
int n = 10;
octagonalSeries(n);
}
/* This code is contributed by Sagar Shukla */
}
计算机编程语言
# Python program to find
# nth octagonal number
def octagonalSeries(n):
for i in range(1, n + 1):
print(3 * i * i - 2 * i,
end = ", ")
# Driver code
n = 10
octagonalSeries(n)
C
// C# program to find
// nth octagonal number
using System;
public class GfG {
// Function to display octagonal series
public static void octagonalSeries(int n)
{
// Formula for finding
//nth octagonal number
for (int i = 1; i <= n; i++)
// Formula for computing
// octagonal number
Console.Write(3 * i * i - 2 * i + ", ");
}
// Driver function
public static void Main()
{
int n = 10;
octagonalSeries(n);
}
}
/* This code is contributed by Vt_m */
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP program to display the
// octagonal series
// Function to display
// octagonal series
function octagonalSeries($n)
{
// Formula for finding
// nth octagonal number
for ($i = 1; $i <= $n; $i++)
// Formula for computing
// octagonal number
echo (3 * $i * $i - 2 * $i),",";
}
// Driver Code
$n = 10;
octagonalSeries($n);
// This code is contributed by Vt_m .
?>
java 描述语言
<script>
// Javascript program to display the
// octagonal series
// Function to display
// octagonal series
function octagonalSeries(n)
{
// Formula for finding
// nth octagonal number
for (let i = 1; i <= n; i++)
// Formula for computing
// octagonal number
document.write(3 * i * i - 2 * i + ", ");
}
// Driver Code
let n = 10;
octagonalSeries(n);
// This code is contributed by _saurabh_jaiswal
</script>
输出:
1, 8, 21, 40, 65, 96, 133, 176, 225, 280
时间复杂度:O(n) T3】辅助空间: O(1)
版权属于：月萌API www.moonapi.com，转载请注明出处
