求第N个余弦正弦数的总和

给定数字N ，任务是找到前N个二十进制正弦数的总和。

The first few Icosidigonal numbers are 1, 22, 63, 124, 205, 306 … 
 

例子：

Input: N = 3 
Output: 86 
Explanation: 
1, 22 and 63 are the first three Icosidigonal numbers.
Input: N = 6 
Output: 721 
 

方法：

1. 最初，我们需要创建一个函数来帮助我们计算第N^个正弦数。
2. 现在，运行开始从1到N循环，找到^第i^个icosidigonal号码。
3. 将所有以上计算出的二十边形数字相加。
4. 最后，显示前N个二十进制对角线数字的总和。

下面是上述方法的实现：

C++

// C++ program to find the sum of the
// first N icosidigonal numbers
#include 
using namespace std;
 
// Function to find the
// N-th icosidigonal number
int Icosidigonal_num(int n)
{
     
    // Formula to calculate
    // nth icosidigonal number
    return (20 * n * n - 18 * n) / 2;
}
 
// Function to find the sum of the
// first N icosidigonal number
int sum_Icosidigonal_num(int n)
{
     
    // Variable to store the sum
    int summ = 0;
     
    // Iterating in the range 1 to N
    for(int i = 1; i < n + 1; i++)
    {
         
        // Finding the sum
        summ += Icosidigonal_num(i);
    }
    return summ;
}
 
// Driver code
int main()
{
    int n = 6;
     
    // Display first Nth
    // icosidigonal numbers
    cout << sum_Icosidigonal_num(n);
}
 
// This code is contributed by coder001

Java

// Java program to find the sum of the
// first N icosidigonal numbers
class GFG{
     
// Function to find the
// N-th icosidigonal number
public static int Icosidigonal_num(int n)
{
         
    // Formula to calculate
    // nth icosidigonal number
    return (20 * n * n - 18 * n) / 2;
}
     
// Function to find the sum of the
// first N icosidigonal number
public static int sum_Icosidigonal_num(int n)
{
         
    // Variable to store the sum
    int summ = 0;
         
    // Iterating in the range 1 to N
    for(int i = 1; i < n + 1; i++)
    {
 
       // Finding the sum
       summ += Icosidigonal_num(i);
    }
    return summ;
}
 
// Driver code   
public static void main(String[] args)
{
    int n = 6;
     
    // Display first Nth
    // icosidigonal numbers
    System.out.println(sum_Icosidigonal_num(n));
}
}
 
// This code is contributed by divyeshrabadiya07

Python3

# Python3 program to find the
# sum of the first N 
# Icosidigonal numbers
 
# Function to find the
# N-th Icosidigonal
# number
def Icosidigonal_num(n):
  
    # Formula to calculate 
    # nth Icosidigonal
    # number
    return (20 * n * n -
            18 * n) // 2
     
   
# Function to find the
# sum of the first N
# Icosidigonal number
def sum_Icosidigonal_num(n) :
     
    # Variable to store
    # the sum
    summ = 0
     
    # Iterating in the range
    # 1 to N
    for i in range(1, n + 1):
 
        summ += Icosidigonal_num(i)
     
    return summ
   
# Driver code
if __name__ == '__main__' :
           
    n = 6
     
 
    print(sum_Icosidigonal_num(n))

C#

// C# program to find the sum of the
// first N icosidigonal numbers
using System;
 
class GFG{
         
// Function to find the
// N-th icosidigonal number
static int Icosidigonal_num(int n)
{
             
    // Formula to calculate
    // nth icosidigonal number
    return (20 * n * n - 18 * n) / 2;
}
         
// Function to find the sum of the
// first N icosidigonal number
static int sum_Icosidigonal_num(int n)
{
             
    // Variable to store the sum
    int summ = 0;
             
    // Iterating in the range 1 to N
    for(int i = 1; i < n + 1; i++)
    {
         
       // Finding the sum
       summ += Icosidigonal_num(i);
    }
    return summ;
}
     
// Driver code
public static void Main(string[] args)
{
    int n = 6;
         
    // Display first Nth
    // icosidigonal numbers
    Console.WriteLine(sum_Icosidigonal_num(n));
}
}
 
// This code is contributed by AnkitRai01

Javascript

    // Javascript program to find the sum of the
    // first N icosidigonal numbers
     
    // Function to find the 
    // N-th icosidigonal number 
    function Icosidigonal_num(n) 
    {
 
        // Formula to calculate 
        // nth icosidigonal number
        return (20 * n * n - 18 * n) / 2;
    }
 
    // Function to find the sum of the
    // first N icosidigonal number 
    function sum_Icosidigonal_num(n)
    {
 
        // Variable to store the sum
        let summ = 0;
 
        // Iterating in the range 1 to N
        for(let i = 1; i < n + 1; i++)
        {
 
            // Finding the sum
            summ += Icosidigonal_num(i);
        }
        return summ;
    }
     
    let n = 6;
       
    // Display first Nth 
    // icosidigonal numbers
    document.write(sum_Icosidigonal_num(n));
 
// This code is contributed by divyesh072019.

输出：

721

时间复杂度： O(N)。