fibonacci series used to find the nth term of every series
$ f = array ( ) ; $ f [ 0 ] = 0 ; $ f [ 1 ] = 1 ; for ( $ i = 2 ; $ i < $ n ; $ i ++ ) $ f [ $ i ] = $ f [ $ i - 1 ] + $ f [ $ i - 2 ] ; for ( $ i = 0 ; $ i < $ m ; $ i ++ ) {