DECLARE FUNCTION Pot2& (expo&, md&)
DECLARE FUNCTION IsPrime& (prime&)
DEFLNG A-Z
CLS
PRINT "Mersenne 1.0"
PRINT
DO
   INPUT "p=", p
LOOP UNTIL IsPrime(p) AND (p MOD 2 = 1)
PRINT "M"; p; "= 2 ^"; p; "-1"
PRINT
prime = 1
DO
   prime = prime + 2 * p
   IF prime MOD 8 = 1 OR prime MOD 8 = 7 THEN
      IF IsPrime(prime) THEN
         pt = Pot2(p, prime)
         LOCATE CSRLIN, 1: PRINT prime; pt;
         IF pt = 1 THEN PRINT "Fator :"; prime: SYSTEM
      END IF
   END IF
LOOP UNTIL prime > 2 ^ (p \ 2)
PRINT "Primo"
SYSTEM

FUNCTION IsPrime (prime)
FOR i = 3 TO SQR(prime) STEP 2
   IF prime MOD i = 0 THEN EXIT FUNCTION
NEXT
IsPrime = -1
END FUNCTION

FUNCTION Pot2 (expo, md)
a = 2
FOR i = 2 TO expo: a = (2 * a) MOD md: NEXT
Pot2 = a
END FUNCTION