I am pretty certain something is wrong. I'm doing the clojure version and am getting:

[53 83 54 -58 -20 56 57 10] as input to lcmu
my code generates:
[53 4399 237546 6888834 68888340 964436760 18324298440 18324298440]
but the test expects:
[53 4399 237546 6888834 68888340 964436760 18324298440 5722146280]

I can't see how this possibly could be correct?

He made the same solution as I did. The idea is pretty much what you said;
For each possible side length a, get each possible side length b >= a, and then calculate u=c^2.

Finally just check that c is an integer (or rather calculate c, followed by checking that c^2 = u), and that it has an acceptable perimeter.

And then count how many solutions there are. (I guess you did three loops, a, b, c? Or trying to find all for a given perimeter?)

I'm having the exact same problem and have no idea of how to check what the inputs are.