Set movie dimensions 230 x 100 (or any desired) with Frame > Frame Size
Choose "Frame" > "Insert", put Count: 6 and duration 2 seconds
Change frame 1 delay to "0.05".
Choose "Frame" > "ActionScript" and paste the code:
// generate random number (f) but different than the last one (l)
// the number will be between 1 and 6
while(f==l) { f = Math.Floor(Math.Random()*6)+1; }
// remember the last random number
l = f;
// jump to a frame
if(f==1) gotoAndPlay("Frame 2");
if(f==2) gotoAndPlay("Frame 3");
if(f==3) gotoAndPlay("Frame 4");
if(f==4) gotoAndPlay("Frame 5");
if(f==5) gotoAndPlay("Frame 6");
if(f==6) gotoAndPlay("Frame 7");
Put graphics on each frame (from Frame 2 to Frame 7) for example numbers
For each Frame 2 to Frame 7 choose "Frame" > "Loop" and select "After this frame jump to frame:" Frame 1.
Choose "Movie" > "Export Options" and change "SWF Version": Flash Player 6.