Write a C program to print the solution of the series f(n)= (1) + (2*3) + (4*5*6) ... upto n terms using recursion.

 Source code:

/* Program to print the solution of the series  f(n)= (1) + (2*3) + (4*5*6) ... upto n terms using recursion.*/

#include <stdio.h>

int seriesSum(int calculated, int current, int N)

{

    int i, cur = 1;

    // checking termination condition

    if (current == N + 1)

        return 0;

    // product of terms till current

    for (i = calculated; i < calculated + current; i++)

        cur *= i;

    // recursive call for adding terms next in the series

    return cur + seriesSum(i, current + 1, N);

}

int main()

{

    int N;

    printf("Enter the nth term: ");

    scanf("%d", &N); /* Enter number to terms N to be calculated */

    /* Write the function int seriesSum(int calculated, int current, int N) which finds the sum of the series

using recursion.  calculated - number of terms till which sum of terms has 

been calculated; current - number of terms for which sum has to be calculated; N - Number of terms in the function to be calculated */

    printf("The result of the series is: %d\n", seriesSum(1, 1, N));

    return 0;

}

Output: