Below are the suggested tri-coin variants and their associated values. I wanted to go with a theme related to 3 because triangles are made up of 3 edges/points, so every coin is worth 3 times as much as the previous.

The order is yellow, green, blue, purple, red, white, and black. I can't see any reason to make a coin worth more than 729 because they are already getting ridiculously high.