RosettaCodeData/Task/Loops-Increment-loop-index-within-loop-body/BASIC256/loops-increment-loop-index-within-loop-body.basic

function isPrime(number)
    if (number % 2 = 0) or (number % 3 = 0) then return false
    lim = sqr(number)

    for i = 5 to lim step 2
        if number % i = 0 then return false
    next i

    return true
end function

i = 42
counter = 0
while counter < 42
    if isPrime(i) then
        counter += 1
        print "n = "; counter, i
        i += i - 1
    end if
    i += 1
end while
end