text: Tridecagonal Number | Java program to find N - th tridecagonal number ; Function to find N - th tridecagonal number ; Formula to calculate nth tridecagonal number ; Driver Code
code: class GFG { static int Tridecagonal_num ( int n ) { return ( 11 * n * n - 9 * n ) / 2 ; } public static void main ( String [ ] args ) { int n = 3 ; System . out . print ( Tridecagonal_num ( n ) + "NEW_LINE"); n = 10 ; System . out . print ( Tridecagonal_num ( n ) + "NEW_LINE"); } }