Centered polygonal number

Centered polygonal numbers are a class of figurate numbers that represent a specific arrangement of points that form a polygon with an additional central point. The shape can be thought of as a polygon (such as a triangle, square, pentagon, etc.) with a point in the center and successive layers of points surrounding that central point. The \(n\)-th centered \(k\)-gonal number represents the number of dots that can be arranged in a centered \(k\)-gonal shape.