Driver code
$ N = 17 ; echo " Mobius ▁ Functions ▁ M ( N ) ▁ at ▁ N ▁ = ▁ " , $ N , " ▁ is : ▁ " , mobius ( $ N ) , " STRNEWLINE " ; echo " Mobius ▁ Functions ▁ M ( N ) ▁ at ▁ N ▁ = ▁ " , 25 , " ▁ is : ▁ " , mobius ( 25 ) , " STRNEWLINE " ; echo " Mobius ▁ Functions ▁ M ( N ) ▁ at ▁ N ▁ = ▁ " , 6 , " ▁ is : ▁ " , mobius ( 6 ) ; ? >