identification division.
program-id. prog.
environment division.
data division.
working-storage section.
  77 n pic Z9.
  77 i pic Z9.
  77 r pic Z9.
procedure division.
  display 'Hello, World!'
  accept n
  move 0 to i
  perform until i>n
    compute r = 2**i
    display r
  end-perform.
  stop run.