# Heptacontagon Number

• Last Updated : 23 Jun, 2021

Given a number N, the task is to find Nth Heptacontagon number

A Heptacontagon number is class of figurate number. It has 70 – sided polygon called heptacontagon. The N-th heptacontagon number countâ€™s the 70 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few heptacontagonol numbers are 1, 70, 207, 412 …

Examples:

Input: N = 2
Output: 70
Explanation:
The second heptacontagonol number is 70.
Input: N = 3
Output: 207

Approach: The N-th heptacontagon number is given by the formula:

• Nth term of s sided polygon =

• Therefore Nth term of 70 sided polygon is

•

Below is the implementation of the above approach:

## C++

 // C++ program for above approach#include using namespace std; // Finding the nth heptacontagon numberint heptacontagonNum(int n){    return (68 * n * n - 66 * n) / 2;} // Driver codeint main(){    int N = 3;         cout << "3rd heptacontagon Number is = "         << heptacontagonNum(N);     return 0;} // This code is contributed by shivanisinghss2110

## C

 // C program for above approach#include #include  // Finding the nth heptacontagon Numberint heptacontagonNum(int n){    return (68 * n * n - 66 * n) / 2;} // Driver codeint main(){    int N = 3;    printf("3rd heptacontagon Number is = %d",           heptacontagonNum(N));     return 0;}

## Java

 // Java program for the above approachclass GFG{ // Finding the nth heptacontagon numberstatic int heptacontagonNum(int n){    return (68 * n * n - 66 * n) / 2;} // Driver Codepublic static void main(String[] args){    int N = 3;    System.out.println("3rd heptacontagon Number is = " +                                    heptacontagonNum(N));}} // This code is contributed by rutvik_56

## Python3

 # Python3 program for above approach # Finding the nth heptacontagon Numberdef heptacontagonNum(n):     return (68 * n * n - 66 * n) // 2; # Driver codeN = 3;print("3rd heptacontagon Number is =",                 heptacontagonNum(N)); # This code is contributed by Akanksha_Rai

## C#

 // C# program for the above approachusing System;class GFG{ // Finding the nth heptacontagon numberstatic int heptacontagonNum(int n){    return (68 * n * n - 66 * n) / 2;} // Driver Codepublic static void Main(){    int N = 3;    Console.Write("3rd heptacontagon Number is = " +                               heptacontagonNum(N));}} // This code is contributed by Akanksha_Rai

## Javascript

 
Output:
3rd heptacontagon Number is = 207

Time Complexity: O(1)

Auxiliary Space: O(1)

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