Frobenius Number

# Finding Frobenius Number of a Set

testSet = [6, 9, 20] # Set to test

def findGCF(s): # Finds greatest common factor of a list
    factors = list(range(1,max(s)+1))
    for i in s:
        temp = []
        for f in factors:
            temp.append(f)
        for k in temp:
            if i%k!=0:
                factors.remove(k)
    return max(factors)

print("These numbers can\'t be created with the numbers in your set:")
gcf = findGCF(testSet)
if gcf>1:
    print("Any number that is not divisible by %s" % gcf)
    for i in range(len(testSet)):
        testSet[i]/=gcf
consecPoss = 0
num = 0
impossNums = []
while consecPoss < min(testSet):
    impossible = True
    num+=1
    if num < min(testSet):
        impossNums.append(num)
    else:
        for n in testSet:
            if (num >= n) and ((num - n) not in impossNums):
                impossible = False
        if impossible:
            impossNums.append(num)
            consecPoss = 0
        else:
            consecPoss += 1
for i in impossNums:
    printNum = i*gcf
    print(printNum)