Narrated Anas: The Prophet (ﷺ) said, "If anyone forgets a prayer he should pray that prayer when he remembers it. There is no expiation except to pray the same." Then he recited: "Establish prayer for My (i.e. Allah's) remembrance." (20.14).
The chain is ordered from the source of the saying to the compiler: 1 = the speaker/first transmitter, the following links those who passed it on in turn, and at the bottom al-Bukhari who compiled the work. Click a narrator to list every hadith in which he appears; the number in parentheses is how many hadiths across the collections on this site the narrator appears in.