 Square triangular number

A square triangular number is a number that is both a perfect square and a triangular number. A triangular number is a number that can be arranged in the shape of an equilateral triangle. The \(n\)-th triangular number is given by the formula: \[ T_n = \frac{n(n + 1)}{2} \] where \(n\) is a positive integer. A perfect square is a number that can be expressed as the square of an integer.