The Instance Range texture holds a greyscale color with the range of 0 - Maximum ID, and prepares this range to map to geometric instance IDs. This node has one parameter, Maximum ID, which should correspond to the total number of instanced geometry in the scene that the material applies to. The Instance Range node can be connected to other nodes such as an Octane Gradient Texture node to create color variations based on the instance IDs (figure 1).
Figure 1: The Instance Range node used to spread a Gradient Texture's colors across a series of instanced cubes