Question 335383
<pre><b>
Triangle 1, the first triangle, has 1 = {{{3^0}}} dots
Triangle 2, the second triangle, has 3 = {{{3^1}}} dots
Triangle 3, the third triangle, has 9 = {{{3^2}}} dots

So it looks like the exponent of 3 in the number of dots
is 1 less than the triangle number, so

Triangle n, the nth triangle, has {{{3^(n-1)}}} dots.

Edwin</pre>