procedure main()
    I_START := 42
    LIMIT := I_START

    i := I_START
    n := 0
    until n = LIMIT do {
        if is_prime(i) then {
            n +:= 1
            write(right(n,2),": ",comma_string(i))
            i +:= i
        } else
            i +:= 1
    }
end

procedure is_prime(n)
    if n < 2 then fail
    if n%2 = 0 then return n = 2
    if n%3 = 0 then return n = 3
    d := 5
    while d*d <= n do {
        if n%d = 0 then fail
        d +:= 2
        if n%d = 0 then fail
        d +:= 4
    }
    return n
end

procedure comma_string(n)
    s := ""
    n ? {
        tab(0)
        while s := "," || move(-3) || s
        if pos(1) then s := s[2:0]
        else s := tab(1) || s
    }
    return s
end