Generate an incrementally increasing sequence like 112123123412345

Question

Basically I want to generate a sequence, say:

n is 2, the sequence will be 112
n is 3, sequence is 112123
n is 5, sequence is 112123123412345

I did

Answer 1

Here is one possibility:

n<-5
unlist(lapply(1:n,function(x) 1:x))
## [1] 1 1 2 1 2 3 1 2 3 4 1 2 3 4 5