Is it SQUARE or TRIANGULAR ?!

This app helps you to figure out whether a number is square or triangular

"In mathematics, a square triangular number (or triangular square number) is a number which is both a triangular number and a perfect square. There are infinitely many square triangular numbers; the first few are 0, 1, 36, 1225, 41616, 1413721, 48024900, 1631432881, 55420693056, 1882672131025 (sequence A001110 in the OEIS)."

wikipedia : https://en.wikipedia.org/wiki/Triangular_number