I need to create a row of numbers according to this:

Form such a series of 35 numbers, consisting of the digits 1, 2, 3, 4, 5, 6 and 7, each of these digits will be contained in the series exactly five times. Two digits (e.g., 1 and 2) will be in the row at most once. There will always be one different digit between two identical digits (e.g. 1 and 1).

Something like this: 1,2,3,4,5,6,7,2,1,4,3,6,5,7,3,2,5,4,7,6,1,4,3,6,5,1,7,2,5,4,7,6,1,2,3

however, the rules are strict:

two digits can not repeat more than once
the same digits cannot be next to each other
Is there a way how to create this? Is it possible to find out how many possibilities there are to arrange such a sequence?

thanks!