Sequence length encoding using R

Is there a way to encode increasing integer sequences in R, analogous to encoding run lengths using run length encoding (rle)?

I'll illustrate with an example:

Analogy: Run length encoding

r <- c(rep(1, 4), 2, 3, 4, rep(5, 5))
rle(r)
Run Length Encoding
  lengths: int [1:5] 4 1 1 1 5
  values : num [1:5] 1 2 3 4 5

Desired: sequence length encoding

s <- c(1:4, rep(5, 4), 6:9)
s
[1] 1 2 3 4 5 5 5 5 6 7 8 9

somefunction(s)
Sequence lengths
  lengths: int [1:4] 5 1 1 5
  value1 : num [1:4] 1 5 5 5

Edit 1

Thus, somefunction(1:10) will give the result:

Sequence lengths
  lengths: int [1:1] 10
  value1 : num [1:1] 1 

This results means that there is an integer sequence of length 10 with starting value of 1, i.e. seq(1, 10)

Note that there isn't a mistake in my example result. The vector in fact ends in the sequence 5:9, not 6:9 which was used to construct it.

My use case is that I am working with survey data in an SPSS export file. Each subquestion in a grid of questions will have a name of the pattern paste("q", 1:5), but sometimes there is an "other" category which will be marked q_99, q_other or something else. I wish to find a way of identifying the sequences.

Edit 2

In a way, my desired function is the inverse of the base function sequence, with the start value, value1 in my example, added.

lengths <- c(5, 1, 1, 5)
value1 <- c(1, 5, 5, 5)

s
[1] 1 2 3 4 5 5 5 5 6 7 8 9
sequence(lengths) + rep(value1-1, lengths) 
[1] 1 2 3 4 5 5 5 5 6 7 8 9

Edit 3

I should have stated that for my purposes a sequence is defined as increasing integer sequences a