Driver Code
$ n = 4 ; echo $ n , " th ▁ Icosidigonal ▁ number ▁ : ▁ " , icosidigonal_num ( $ n ) ; echo " STRNEWLINE " ; $ n = 8 ; echo $ n , " th ▁ Icosidigonal ▁ number ▁ : ▁ " , icosidigonal_num ( $ n ) ; ? >