Looks like there's some simple issue with the code. To assist with getting the Steinhart-Hart equation parameters right, you can refer to the part specifications.

That refers to the "M" curve.

From the website, we get:

Which gives you the resistance values for various temperatures (multiply by 1000 for the values of your part in ohms).

Then, you can calculate the Steinhart-Hart parameters directly (from the Wikipedia page)

Or you can try this online calculator (I have not verified it is accurate)

In either case, optimize the thermistor linearization by picking three temperatures well spaced apart covering your range of interest.

Looks like there's some simple issue with the code.

To assist with getting the Steinhart-Hart equation parameters right, you can refer to the part specifications.

That refers to the "M" curve.

From the website, we get:

Which gives you the resistance values for various temperatures (multiply by 1000 for the values of your part in ohms).

Then, you can calculate the Steinhart-Hart parameters directly (from the Wikipedia page)

Or you can try this online calculator (I have not verified it is accurate)

In either case, optimize the thermistor linearization by picking three temperatures well spaced apart covering your range of interest.