The Sequential Index column displays a hierarchical number corresponding to an item's position within the structure.
The first number in the index represents the top level of the hierarchy, the next number (after the period) refers to the second level, etc. To better understand how this works, let's look at the above example:
Epic 1 has a sequential index of 1, because it is the first item in the top level of the hierarchy.
Story 2 has a sequential index of 1.2, because it is the second child under Epic 1.
Bug 1 has a sequential index of 1.2.1, because it is the first child under Story 2.
Task has a sequential index of 2.1.1, because Epic 2 is second item in top level, Story 4 is the first item beneath it, and Task is the first child beneath that.
The Sequential Index attribute works different depending on whether you're viewing it in a column or using it in a formula:
The Sequential Index column ignores Filter Transformations, so even if you see only a part of a structure, the numbers will still show the position of the item in the unfiltered structure.
When you use Sequent Index in a formula, Filter Transformations are taken into consideration and will affect your final calculation.
Filter generators always affect the Sequential Index because they change the underlying structure.
