List problem -> mapping

Question

Given a sequence of 0 and 1.
do the following from right to left:
1st number * 1
2nd number * 2
3rd number * 4
4th number * 3

5th number * 1
6th number * 2
7th number * 4
8th number * 3

...

at last step sum it.

eg: 100111011
100213021
1+2+1+3+2+1 = 10

Answer 1

Do this

num=reversed([int(i) for i in str(x)])
mult=[1,2,4,3]
f_sum=0
for i,j in enumerate(num):
f_sum+=mult[i%4]*j

Answer 2

@Jan Markus Koushik Naskar nice!

If sum is devisible by 5, the binary is it too.

the sequence for 7 is
1 2 4 1 2 4...

for 9:
1 2 4 8 7 5 1 2 4 5...

if sum is devisible by 7 / 9 the binary is it too.