How do I display all the combinations of a group of numbers

Example
Cell A1='3'
Cells B1='1', B2=3, B3=9, B4=20, B5=25

This will display all the combinations of 3(A1) numbers from the numbers
1,3,9,20,25

1 3 9
1 3 20
1 3 25 etc

The amount in cell A1 will change as well as the total of numbers in the
range.