#17

INCREASE M 

PRINT X

REPEAT X TIMES ( INCREASE S REPEAT X TIMES ( INCREASE P ) )

REPEAT S TIMES ( CLEAR S INCREASE S REPEAT M TIMES ( CLEAR M CLEAR S ) )

INCREASE M
INCREASE M

REPEAT P TIMES (
 REPEAT S TIMES (

 # Is even? and halve anyways
 CLEAR G
 CLEAR B
 CLEAR A
 REPEAT X TIMES (
   INCREASE B
   REPEAT A TIMES (
    CLEAR A
    CLEAR B
   )
   REPEAT B TIMES (
    INCREASE A
    INCREASE G
   )
  )
 CLEAR I
 INCREASE I
 # Was uneven???
 REPEAT B TIMES (
  CLEAR I
  REPEAT X TIMES ( REPEAT M TIMES ( INCREASE X ) )
  INCREASE X
 )

 REPEAT I TIMES (
  PRINT G # if was half print half
  # 1 always comes after 2 so check if we should continue
  CLEAR S
  CLEAR X
  REPEAT G TIMES ( INCREASE X INCREASE S REPEAT I TIMES ( CLEAR S CLEAR I ) ) # Set S=G-1 and X=S
  REPEAT S TIMES( CLEAR S INCREASE S ) # continue or not if X was 1
 )

 REPEAT B TIMES ( PRINT X ) # was x*3+1 so print

 )
)