100 PRINT CHR$(147); CHR$(18); "****  MILLER-RABIN PRIMALITY TEST   ****": PRINT
110 INPUT "NUMBER TO TEST"; N$
120 N = VAL(N$): IF N < 2 THEN 110
130 IF 0 = (N AND 1) THEN PRINT "(EVEN)": GOTO 380
140 INPUT "ITERATIONS"; K$
150 K = VAL(K$): IF K < 1 THEN 140
160 PRINT
170 DEF FNMD(M) = M - N * INT(M / N)
180 D = N - 1
190 S = 0
200 D = D / 2: S = S + 1
210 IF 0 = (D AND 1) THEN 200
220 P = 1
230 FOR I = 1 TO K
240 : A = INT(RND(.) * (N - 2)) + 2
250 : X = 1
260 : FOR J = 1 TO D
270 :   X = FNMD(X * A)
280 : NEXT J
290 : IF (X = 1) OR (X = (N - 1)) THEN 360
300 : FOR J = 1 TO S - 1
310 :   X = FNMD(X * X)
320 :   IF X = 1 THEN P = 0: GOTO 370
330 :   IF X = N - 1 THEN 360
340 : NEXT J
350 : P = 0: GOTO 370
360 NEXT I
370 P = P * (1 - 1 / (4 * K))
380 IF P THEN PRINT "PROBABLY PRIME ( P >="; P; ")": END
390 PRINT "COMPOSITE."