Sum of series formed by difference between product and sum of N natural numbers | Java program to calculate the sum upto the Nth term of the given series ; Recursive Function to calculate the sum upto Nth term ; If N - th term is calculated ; Update multi to store product upto K ; Update add to store sum upto K ; Update prevSum to store sum upto K ; Proceed to next K ; Function to calculate and return the Sum upto Nth term ; Recursive Function ; Driver code
class GFG { static int seriesSumUtil ( int k , int n , int prevSum , int multi , int add ) { if ( k == n + 1 ) { return prevSum ; } multi = multi * k ; add = add + k ; prevSum = prevSum + multi - add ; return seriesSumUtil ( k + 1 , n , prevSum , multi , add ) ; } static int seriesSum ( int n ) { if ( n == 1 ) return 0 ; int prevSum = 0 ; int multi = 1 ; int add = 1 ; return seriesSumUtil ( 2 , n , prevSum , multi , add ) ; } public static void main ( String [ ] args ) { int N = 5 ; System . out . println ( seriesSum ( N ) ) ; } }