Given an integer N the task is to print the F(N)th term in Java

Print F(N)th term in Java

Here, in this page we will discuss the program to print the F(N)th term in java.  A function f is defined as follows F(N)= (1) +(2*3) + (4*5*6) … N. We are given with an integer N and we need to print the F(N)th term.

Example :

  • Input : 4
  • Output : 5167
  • Explanation : 1 + (2*3) + (4*5*6) + (7*8*9*10) = 5167.
Print F(N)th term in Java

We can solve this using two methods that is listed below 

  • Using Recursion 
  • Using loop 

Method 1 (Using Recursion) :

  • Create a recursive function say term(int calculated, int current, int N)
  • Declare a variable cur to hold the product of the terms and initialize it with 1.
  • Base condition will be if(current == N+1) then, return 0. Here, current denotes the current term of the series.
  • Now, run a loop to calculate the product of terms till current.
  • Set i= calculate. Termination condition of the loop will be i>= calculated + current.
  • Inside loop set cur *= i
  • After execution of loop return cur + term(i, current+1, N)
Print F(N)th term in java

Java code

Run
class Main
{
  public static void main (String args[])
  {
    int n = 3;
    System.out.println (term (1, 1, n));
  }
// Recursive function 
  static int term (int calculated, int current, int N)
  {
    int i, cur = 1;
    // Base Condition
    if (current == N + 1)
      return 0;
    // product of terms till current
    for (i = calculated; i < calculated + current; i++)
      cur *= i;
    return cur + term (i, current + 1, N);
  }
}
Output :

127

Method 2 (Using Loop) :

  • Create a function say term(int calculated, int current, int N) to calculate the required N-th term.
  • Declare a variable result = 0.
  • Run a while loop till current != N+1.
  • Inside while loop declare a variable cur to hold the product of the terms and initialize it with 1.
  • Now, run a loop to calculate the product of terms till current.
  • Set i= calculate. Termination condition of the loop will be i>= calculated + current.
  • Inside for loop set cur *= i.
  • After execution of for loop set calculated = i, result += curr and increment current value by 1.
  • After the execution of while loop return result.

Java Code

Run
class Main
{
  public static void main (String args[])
  {
    int n = 3;
      System.out.println (term (1, 1, n));
  }
//Function to calculate N-th term
  static int term (int calculated, int current, int N)
  {
    int i, result = 0;
    while (current != N + 1)
      {
    int cur = 1;
    // product of terms till current
    for (i = calculated; i < calculated + current; i++)
      cur *= i;
    calculated = i;
    result += cur;
    current++;
      }
    return result;
  }
}

Output

127