Visual Sequence Analysis: Finding the Term-to-Term Rule in Bar Patterns

Question

What is the term-to-term rule for the above sequence?

00:00 Find the sequence formula

00:04 Let's observe the number of lines in each term

00:20 Let's substitute the first term in equations and see if it fits

00:31 We can see this formula doesn't fit

00:38 We'll continue with this method until we find the correct formula

00:44 This formula fits the first term

00:53 This formula doesn't fit

01:00 And this one doesn't fit either

01:05 And this is the solution to the question

$-n+6$