“When a mysterious stranger thwarts a sophisticated attempt on her life, an isolated mathematical genius must leave behind everything she knows to flee cross-country with her new-found protector in search of clues to the motives and identities of her would-be assassins.” (41 words)

So what exactly is her goal? What does she intend to do once she’s discovered the identities and motives of these assassins?

I think you add a little too much description. Here’s an example, just cutting out some of the unnecessary words.

After an attempt on her life is thwarted, an isolated mathematical genius must flee cross-country with her new companion to investigate the people trying to kill her. (27)

I have a few questions that don’t need to be answered in the logline, but I’m asking you because you should know. What is the motivation of the mysterious stranger? Why is he/she helping her?
Also, what is the motivation of the antagonists? Why do they want her dead?

Something I do for my stories is to create a logline from the antagonist’s perspective, to flesh out their motivation. I also do it for any of the major supporting characters in the story.

The biggest problem I see is that your logline doesn’t present and show off a hook. What makes this story special, unique? If a producer were presented with two loglines for thriller concepts, what would make them want to read your script over the other? Find the hook, the something interesting and put it front and center in the logline. So it can hook the reader.

I hope this helps.