How could I improve?

Lets face it /prog/, I'm a shitty programmer.
How would you improve upon these functions?
It's a couple of functions I was gonna use for writing a primes function utilizing the sieve of Erastothenes.


(defun make-prime-array (n)
  (let ((output (make-array (1- n))))
    (loop for i from 2 to n do
     (setf (aref output (- i 2)) i))
    output))


(defun clean-array (arr n )
  (let ((output nil))
    (loop for i across arr do
     (if (/= (mod i n) 0)
         (push i output))
     (if (= i n)
         (push i output)))
    (reverse output)))


(defun make-array-list (lst)
  (let ((output (make-array (length lst))))
    (loop for i from 0 to (1- (length lst)) do
     (setf (aref output i) (nth i lst)))
    output))

Rewrite them in a good programming language, such as Java!