[tex]\bf \begin{array}{llll} ordinal&term&\stackrel{(a_{n-1})^2}{value}\\ \cline{1-3} 1&a_1&2\\\\ 2&a_2&(a_{2-1})^2\\ &&(a_1)^2\\ &&2^2\\ &&4\\\\ 3&a_3&(a_{3-1})^2\\ &&(a_{2})^2\\ &&4^2\\ &&16\\\\ 4&a_4&(a_{4-1})^2\\ &&(a_{3})^2\\ &&256 \end{array}[/tex]
