C++ program to find n-th term of series 2, 10, 30, 68, 130 …

In this problem, we are given an integer N. The task is to find the n-th term in series 2, 10, 30, 68, 130...

Let’s take an example to understand the problem,

Input

N = 7

Output

350

Explanation

The series is 2, 10, 30, 68, 130, 222, 350...

Solution Approach

A simple solution to the problem is by finding the general term of the series. Here, the Nth term of the series is N^3 + N. This is found by subtracting the current element with the current index.

For i, i = 1, T(1) = 2 = 1 + 1 = 1^3 + 1 i = 2, T(1) = 10 = 8 + 2 = 2^3 + 2 i = 3, T(1) = 30 = 27 + 3 = 3^3 + 2

Program to illustrate the working of our solution,

Example

 Live Demo

#include <iostream> using namespace std; int findNthTerm(int N) {    return ((N*N*N) + N); } int main() {    int N = 8;    cout<<"The "<<N<<"th term of the series is "<<findNthTerm(N);    return 0; }

Output

The 8th term of the series is 520