I need to find sequential number in a row of random numbers and return those numbers separated by a comma or return a blank cell if no sequential numbers are found

For example

A1 | A2 | A3 | A4 | A5 | A6 | A7 |
23 17 19 20 42 74 19,20
45 23 27 36 83 48
13 14 42 46 78 18 13,14

Seems easy but I don't often use excel so I am lost....