    1PRINT "pgms.prime.sieve.siev89/11a.nxtprime/qbas"
    2PRINT "next primes -- trial division. Quickbasic etc."
    3PRINT "by Don.McDonald@welcom.gen.nz,  28.04.97"
    4PRINT 
    5INPUT "start = "; s
    6s% = INT(s / 2) * 2 + 1
    7IF s% < 5 THEN s% = 5 : PRINT "only even prime = 2.  next pr = 3."
    8PRINT  "odd = "; s%
    9PRINT  "next primes,  (cont. after every odd_square.)"
   10TRACE OFF
   11ii = 0
   12FOR x% = s% TO 2 ^ 30.99 STEP 2   :
   13REM tested Acorn A4000 BBC basic V** max=  2^30.99 // 2^14.99
   14   x2 = SQR(x%)
   15   IF x2 = INT(x2) THEN INPUT " cont./q.uit"; a$ : IF a$ = "q" THEN END : STOP
   16   FOR i% = 3 TO x2 STEP 2
   17      y% = x% / i%
   18      IF y% * i% = x% THEN ii = i% : i% = x2
   19      NEXT i%
   20   IF NOT (y% * ii = x%) THEN PRINT " ";  x%;
   21   NEXT x%
   22END
   23