Puzzle | Program to find number of squares in a chessboard | Function to return count of squares ; ; A better way to write n * ( n + 1 ) * ( 2 n + 1 ) / 6 ; Driver Code
< ? php function countSquares ( $ n ) { return ( $ n * ( $ n + 1 ) / 2 ) * ( 2 * $ n + 1 ) / 3 ; } $ n = 4 ; echo " Count ▁ of ▁ squares ▁ is ▁ " , countSquares ( $ n ) ; ? >