Added.

If Rust has random tests, then close the issue please.

The other problem remains, right?

If the input for that test is 132030240, then the expected answer is right.

Actually, generally accepted best practice is to not use named lambdas. Lambdas should be 'throw away' expressions, not statements and def fn's will usually eek out performance over λ expressions but not by anything really noticeable unless you have some order of op stuff going on. If you really want to make this fn sing, use a generator, ala my fork.