a, b are the arguments

a becomes x, the gcd after the loop using Euclid Algo

int(lcm/a) is y, the lcm

350417903 866449540
[11, 27601766442010420] should equal None

I have received that in the test attempts, with several different cases. I believe that in those cases the"None" is wrong

I got this error for sum_limit=2000000:

[402757, 402761, 402763, 402767, 402769] should equal [1091257, 1091261, 1091263, 1091267, 1091269, 1091273]

Shouldn't the first list be the solution since all are prime and sum is 2,013,817? Is the test case wrong?

the in-build factorial function of math includes that case

This was a fun kata

not really... hard coding a prime list is not a great idea

This is a shorter version of the already posted Miller-Rabin primality test code

I think this is more correct because the input can be a negative number.
And -1 is not used for plurals