Sum of the series 1.2 . 3 + 2.3 . 4 + ... + n ( n + 1 ) ( n + 2 ) | function to calculate sum of series ; Driver Code
< ? php function sumofseries ( $ n ) { return ( $ n * ( $ n + 1 ) * ( $ n + 2 ) * ( $ n + 3 ) / 4 ) ; } echo sumofseries ( 3 ) ; ? >