How does the Start-up color temperature setting relate to Kelvin?

[tardy sequoia]

I have a bunch of Phillips Hue light bulbs some are White Ambiance, some are White and Color Ambiance. I can set a white color temperature from 2000k to 6500K on all of them.
One of the configuration items for the bulbs is Start-up color temperature.
How does the 2000k to 6500k scale relate to the 153-454 scale that's available in this configuration field?

Similarly, I have several Innr brand color bulbs that seem to go from 1800K to 6500K but their Start-up color temperature ranges from 153-555, which doesn't make much sense to me either.

What is the formula to get me from these somewhat random seeming ranges to the better known Kelvin range?

[lilac glen]

Sounds like Mired scale.

150 ~= 6500K
500 ~= 2000K

(it's inverse scale)

[tardy sequoia]

Ah ha! Thank you sir, I would have never come up with that. Also, an internet search did not turn that up in the documentation - at least not in the first 10 or so hits that I read through. Maybe I just looked for the wrong terms...

Great... Now I have to go change a bunch of bulbs because they're not defaulted to the colors I want and it seems that sometimes, they don't all come on at the color temp I specify. I can at least get them to default close to what I want...