Paul Erdős's notes on Egyptian fractions are with Ronald Graham, who has reproduced some of them in Paul Erdős and Egyptian Fractions. Graham mentions one unfinished manuscript in which "it is shown that any integer can be represented as a sum of reciprocals of distinct numbers which each have exactly three prime factors". This was only published in 2015, twenty years after his death. As this commentary aptly notes "Nearly 20 years after his death, the famed mathematician Paul Erdős keeps on publishing, thanks to the conjectures he left behind and the friends who strive to prove them."
