2
3
4

Details

The first number printed is "2" because COUNT was started out at 2 and 2 < 5 is true:

' Loop with LESS THAN ending test
'
LET COUNT = 2            'Statement 1
'
DO WHILE COUNT  < 5      'Statement 2
  PRINT COUNT            'Statement 3
  LET COUNT = COUNT + 1  'Statement 4
LOOP 
END

The program keeps increasing and printing COUNT until COUNT reaches 5. Then it fails the condition 5 < 5 so the program ends. Here is what happens in detail:

COUNT	condition	true or false	what happens
2	2 < 5	true	loop body executed, COUNT increased by 1
3	3 < 5	true	loop body executed, COUNT increased by 1
4	4 < 5	true	loop body executed, COUNT increased by 1
5	5 < 5	false	loop body NOT executed, execution skips to END.

To be sure that your boredom is complete, look at another program:

' Loop with different beginning
'
LET COUNT = -2             'Statement 1
'
DO WHILE COUNT  < 2      'Statement 2
  PRINT COUNT            'Statement 3
  LET COUNT = COUNT + 1  'Statement 4
LOOP 
END

Here COUNT is started out with a value of -2. This is OK. The DO WHILE "gatekeeper" can test negative numbers as well as positive numbers, and -2 is certainly less than 2.