居中的非十边形数字
原文:https://www . geeksforgeeks . org/centered-non decadenal-number/
给定一个 n，求第 n 个个居中的非十边形数。 一个以非十边形数字为中心的代表在连续的非十边形(19 边多边形)图层中的中心点和围绕它的其他点。****
前几个居中的非十边形数字是: 1，20，58，115，191，286，400，533，685，856，1046，1255…………………… 示例:****
Input : 3
Output : 58
Input : 13
Output :1483
在数学中，第 n 个项的中心非十边形数由下式给出:
以下是上述思路的基本实现:
C++
// C++ Program to find
// nth centered
// nonadecagonal number
#include <bits/stdc++.h>
using namespace std;
// centered nonadecagonal
// function
int center_nonadecagon_num( long int n )
{
// Formula to calculate nth
// centered nonadecagonal number
return (19 * n * n - 19 * n + 2) / 2;
}
// Driver Code
int main()
{
long int n = 2;
cout << n << "th centered nonadecagonal number : "
<< center_nonadecagon_num(n);
cout << endl;
n = 7;
cout << n << "th centered nonadecagonal number : "
<< center_nonadecagon_num(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 centered
// nonadecagonal number
import java.io.*;
class GFG {
// centered nonadecagonal
// function
static int center_nonadecagon_num(int n)
{
// Formula to calculate nth
// centered nonadecagonal number
return (19 * n * n - 19 * n + 2) / 2;
}
// Driver code
public static void main (String[] args)
{
int n = 2;
System.out.print ( n + "th centered "
+ "nonadecagonal number : ");
System.out.println (
center_nonadecagon_num(n));
n = 7;
System.out.print ( n + "th centered "
+ "nonadecagonal number : ");
System.out.println(
center_nonadecagon_num(n));
}
}
// This code is contributed by m_kit
Python 3
# Program to find nth
# centered nonadecagonal number
def center_nonadecagon_num(n) :
# Formula to calculate
# nth centered nonadecagonal
# number & return it into
# main function.
return (19 * n * n -
19 * n + 2) // 2
# Driver Code
if __name__ == '__main__' :
n = 2
print(n,"nd centered nonadecagonal " +
"number : ",
center_nonadecagon_num(n))
n = 7
print(n,"nd centered nonadecagonal " +
"number : ",
center_nonadecagon_num(n))
# This code is contributed by ajit
C#
// C# Program to find
// nth centered
// nonadecagonal number
using System;
class GFG
{
// centered nonadecagonal
// function
static int center_nonadecagon_num(int n)
{
// Formula to calculate nth
// centered nonadecagonal number
return (19 * n * n -
19 * n + 2) / 2;
}
// Driver code
static public void Main ()
{
int n = 2;
Console.Write ( n + "th centered " +
"nonadecagonal number : ");
Console.WriteLine(
center_nonadecagon_num(n));
n = 7;
Console.Write( n + "th centered " +
"nonadecagonal number : ");
Console.WriteLine(
center_nonadecagon_num(n));
}
}
// This code is contributed by ajit
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// PHP Program to find
// nth centered
// nonadecagonal number
// centered nonadecagonal
// function
function center_nonadecagon_num( $n )
{
// Formula to calculate nth
// centered nonadecagonal number
return (19 * $n * $n -
19 * $n + 2) / 2;
}
// Driver Code
$n = 2;
echo $n ,"th centered " +
"nonadecagonal number : ",
center_nonadecagon_num($n);
echo "\n";
$n = 7;
echo $n , "th centered " +
"nonadecagonal number : ",
center_nonadecagon_num($n);
// This code is contributed by ajit
?>
java 描述语言
<script>
// Javascript program to find nth centered
// nonadecagonal number
// centered nonadecagonal
// function
function center_nonadecagon_num(n)
{
// Formula to calculate nth
// centered nonadecagonal number
return (19 * n * n - 19 * n + 2) / 2;
}
// Driver Code
var n = 2;
document.write(n + "th centered " +
"nonadecagonal number : ");
document.write(center_nonadecagon_num(n) + "<br>");
n = 7;
document.write(n + "th centered " +
"nonadecagonal number : ");
document.write(center_nonadecagon_num(n));
// This code is contributed by Kirti
</script>
*输出:*
2th centered nonadecagonal number : 20
7th centered nonadecagonal numbe : 400
*时间复杂度:*O(1) T3】辅助空间: O(1)
*参考文献:*T2http://oeis.org/A069132T5】
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