Instructions insufficient. How one is supposed to continue a sequence knowing only the first terms ?
That's mathematically undefined.

Instructions not clear.

The test case assumes that the sum of two UINT_MAX has a 33 long representation in binary. While its representation is 1111 1111 1111 1110 (only 32 digits).
So I cannot pass the test.

Ohhhhh ! Now I understand, I iterated on class_size-- so at the end it would be -1.
Thanks for helping me understand my mistake.

I used a print statement like so

printf("%d\n", class_size)

and it returned -1.

If race is factual, then what is the definition?

I am not 100% sure: am I allowed to use PL/pgSQL?

The error messages are really not helpful in this kata.

Avoid reinventing the wheel ;-)

I have a validation probem when I do
ORDER BY
species;

It does really not like it and really wants ORDER BY species;

In some countries, having a “race” column in a “people” database is illegal and considered the definition of racism.

I understand this is considered “normal” in the United States but this is more of an exception than a generality.

Please consider replacing the “race” column with something more factual.