Then we should also add the following
+S(R1 ∩ R2 ∩ R3) = 100

😃

При подсчёте пользователей нужно пропускать все числа с цифрами 4 или 9.
Если слегка переформулировать - нужно определить, какое число будет стоять на n-м месте в ряду натуральных чисел после исключения из этого ряда всех чисел, содержащих 4 и 9.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1 2 3 5 6 7 8 10 11 12 13 15 16 17 18 20 21 22 23 25 26 27 28 30 31
На 4-м месте стоит 5, на 16-м стоит 20, на 24-м - 30, и т.д.

lol! But how does this work?

Great finding! (un)fortunately it's not tested... After checking, it also fails for 4832 :-(

Here is a fixed fork

if digits(n) == digits(n*n):
        return None

What about 4762? ;)

OP solved it, closing

It is not explicitly stated, but you should consider the following restrictions.
The name of the city must come first in the line. The name of the team must be one word consisting of at least two letters, the first of which is capitalized, the rest - lowercase. Any symbols other than letters of the alphabet are not allowed in the name.

You probably get an error already when the base is 2. This is because with a base of 2, only "digits" less than 2 can be used in writing a number. Just like for any other bases.
And the entry for "12" uses "2".

Согласен