Driver Code
$ n = 2 ; echo $ n , " th ▁ centered ▁ " + " nonadecagonal ▁ number ▁ : ▁ " , center_nonadecagon_num ( $ n ) ; echo " STRNEWLINE " ; $ n = 7 ; echo $ n , " th ▁ centered ▁ " + " nonadecagonal ▁ number ▁ : ▁ " , center_nonadecagon_num ( $ n ) ; ? >