Talk:Number theory

That formula for checking the N-Queens problem is necessary but not sufficient. It effectively calculates the sum numbers such that each number is from a unique row and column. Therefore, a simple counter example is placing the queens along the diagonal. 65.110.240.184 22:11, 17 April 2008 (UTC)

Even more, it isn't sufficient for row and column noncollision either. Por example, on a 4x4 board the numbers could be 1, 5, 12, 16; sum is 34, or (4*(16+1))/2, but the first and fourth columns collide. 189.145.24.116 07:36, 2 August 2009 (UTC)