Тип 8 № 12607

Решение на Python:

from itertools import product
n = 0
for i in product(sorted('0123456789QWERTYUIOPASDFGHJKLZXCVBNM')[:16], repeat=3):
    a = ''.join(i)
    if a[0] != '0':
        if len(a) == len(set(a)):
            a = a.replace('2', '0').replace('4', '0').replace('6', '0').replace('8', '0')
            a = a.replace('A', '0').replace('C', '0').replace('E', '0')
            a = a.replace('3', '1').replace('5', '1').replace('7', '1')
            a = a.replace('9', '1').replace('B', '1').replace('D', '1').replace('F', '1')
            if a.count('11') == a.count('00') == 0:
                n += 1
print(n)

Ответ: 840