Source: wikibot/squared-triangular-number
= Squared triangular number
{wiki=Squared_triangular_number}
A squared triangular number is a special type of number that is both a triangular number and a perfect square. A triangular number is a number that can form an equilateral triangle. The \\( n \\)-th triangular number is given by the formula: \\\[ T_n = \\frac\{n(n + 1)\}\{2\} \\\] A perfect square is an integer that is the square of an integer.