following are the code in c++
#include<bits/stdc++.h>
using namespace std;
//fuction to find nth term of the sequence
int val(int n){
if(n==1){
return 3;
}else{
return val(n-1)+8*pow(2,n-2);
}
}
// driver fuction
int main(){
int n;
cout << "Which element of the sequence would you like to know?\n";
cin >> n;
//checking for input less than 1
do{
if(n<1)
{
cout<<"Please enter a number greater than 0:"<<endl;
cin>>n;
}
}while(n<1);
//printing the output
cout<<n<<"th element of the sequence is: ";
cout << val(n);
}
Explanation:
in the given code, if user enter input less than 1 then it will again ask for the input greater than 0 . When the input is greater than 0,it calls the recursive function with the parameter n .if the input is 1 then function will give 3 as output. And when input is greater than 1, the recursive function will return nth element of the given sequence.
output
which element of the sequence would you like to know?
-1
Please enter a number greater than 0:
0
Please enter a number greater than 0:
5
5th element of the sequence is: 123
