UA 3913 then UA 2613 at Houston
Denver → Houston → Denver
Timetable, Houston time
21:22UA 3913 from Denver at the gate
14:46UA 2613 to Denver leaves the gate
17 h 24 apart on the timetable, overnight
UA 2613 leaves 17 h 24 after UA 3913 arrives on the timetable: more than half a day, so not a connection we count.