That chart is very cool. Yes, I came up with the formula myself. I wanted an exponential function to describe warp factors because I wanted super fast, even ludicrous, speeds but without crazy big warp factors. So the formula had to be a base integer raised to a power of warp. I also needed warp 1 = 1c, so the power had to be zero hence why the number is raised to a power of warp -1. This offsets the warp factor whereby a warp factor of 1 gives a power of 1-1 or 0 which I wanted. Any number raised to the power of 0 is always 1. I picked the base to be 4 just because it seemed to give reasonable speeds that I liked. I wanted ludicrous speeds to be around warp 14 or so. If you want the exponential function to be shallower (higher speeds to rise less sharply) you could go with a base of 2 or 3. If you want the exponential function to rise faster (higher speeds to rise even faster), you could use a base greater than 4. But 4 seemed like a reasonable compromise. With this formula, Star Trek could introduce better warp drives, exotic propulsion systems, even crazy fast speeds as much as the writers want and no matter how fast the ship gets, the warp factors would never get crazy.