Numbers and Arithmetic for Grade 12, Problem ID: 4687

Numbers and Arithmetic K12Savin's problem:

Using each of the digits 1,2,3, and 4 twice, write out an eight-digit number in which there is one digit between the ones, two digits between the twos, three digits between the threes, and four digits between the fours.
How many such numbers?

The number of such numbers is oddThe number of such numbers is evenThere is only one such numberThere are no such numbers