text: Number of coloured 0 's in an N | C # implementation of the approach ; Function to return the count of coloured 0 s in an n - level hexagon ; Driver code
code: using System ; class GFG { static int count ( int n ) { return n * ( 3 * n - 1 ) / 2 ; } public static void Main ( String [ ] args ) { int n = 3 ; Console . WriteLine ( count ( n ) ) ; } }