/*  Collatz conjecture  */
/*  If, odd, increase the number, otherwise, decrease it  */

x : 27$
y : [x]$
while x > 1 do (
  x : if (mod(x, 2) = 1) then
    x*3+1
  else
    x/2,
  y : append(y, [x])
)$
y;
print(length(y), " iterations")$