Sum of first n term of Series 3 , 5 , 9 , 17 , 33. ... | PHP program to find sum of first n terms ; Sn = n * ( 4 * n * n + 6 * n - 1 ) / 3 ; number of terms to be included in sum ; find the Sn
< ? php function calculateSum ( $ n ) { return ( pow ( 2 , $ n + 1 ) + $ n - 2 ) ; } $ n = 4 ; echo " Sum = " ? >