[math-fun] Euler quote (?)

I just Googled the quote “*My pen is a better mathematician than I am*” (which I’m sure I’ve seen attributed to Euler) in search of the original French or Latin phrasing, and was dismayed to see that the only verbatim appearances of this sentence are references to an earlier essay of mine! I’m hoping this quote isn’t an unintentional fabrication on my part. Can anyone provide a source or reference? Thanks, Jim Propp