Puzzle ZQSE 

Workings

Hint
This question involves the months in some way.

Answer
431.

This is the sequence of the length of the name of the month and the number of days in that month. For example, January has 7 letters and 31 days: 731. February has 8 letters and 28 days, etc. The next 3 digits are therefore 431 since July has 4 letters and 31 days.