The problem is that you are reversing the string a few times. The following will do: (defun base8 (n) (let ((t8 (truncate n 8)) (m8 (mod n 8))) (if (= t8 0) (list m8) (append (base8 t8) (list m8))))) EDIT Here's a solution without append, using a helper function.
On average, a kidney weighs approximately 150 to 160 grams and, together, both kidneys weigh about 0.5 percent of total body weight. Usually, the left kidney is slightly larger than the right. These measurements and weights represent the typical ranges of a healthy, adult human kidney.
Urinalysis Specific Gravity (SG): This measures how dilute your urine is. Specific gravity takes into account the weight of the urine and particle size. Water would have a specific gravity of 1.000 Specific gravity between 1.002 and 1.035 on a random sample should be considered normal if kidney function is normal.