ティージェーグレェ (nprofile…0ajr) well, it's a good thing no one has ever broken into an smtp account before.
But no, if you want to compute the TOTP algorithm by hand, I don't think you need apps, but I hope you're also writing your code on paper and submitting your diffs via the post.
Personally I have a pad of 1 time use tokens printed out at home in case my TOTP device becomes unavailable to me.