I have a column of numbers in
assorted sequential but non contiguous blocks from 4 to 30.
I seek a formula to renumber them 1 and onwards,
until a lower number is found, whereupon they would begin again at 1.

Can anyone assist please?

eg:

Col A
2
3
6
8
13
4
5
6
8
12
21

I seek Column B to show
1
2
3
4
5
1
2
3
4
5
6