Name of mathematician who made an error, which made his later work useless?

Question

In school, many years ago, my teacher taught me about a mathematician who was working on developing tables (or something similar to that). He apparently worked for years and then made a single mistake in his calculations. Consequently, the remaining work he did on these tables, which spanned additional years, was inaccurate. I tried looking him up recently but can't find any information in a general search of the internet. Does anyone know who this mathematician was?

Answer 1

William Shanks is probably who they meant