text: Tridecagonal Number | Function to find N - th Tridecagonal number ; Formula to calculate nth Tridecagonal number ; Driver Code
code: function Tridecagonal_num ( n ) { return ( 11 * n * n - 9 * n ) / 2 ; } let n = 3 ; document . write ( Tridecagonal_num ( n ) + " " ) ; n = 10 ; document . write ( Tridecagonal_num ( n ) ) ;