Algorithm to convert any positive integer to an RGB value

Question

We have a heatmap we want to display. The numbers that will make up the values being displayed are unknown (except that they will be positive integers). The range of numbers

Answer 1

Without knowing the range of values, there isn't much you can do to come up with a meaningful function mapping an arbitrary range of positive integers to a heat-map type range of colors.

I think you're going to have to run through your data at least once to get the min/max or know them ahead of time. Once you have that you can normalize appropriately and use any number of color schemes. The simplest solution would be to specify something like "hue" and convert from HSV to RGB.