Create a sequence of sequences of numbers

Question

The following sequence should be created in R using rep or another function.

Basically, c(1, 2, 3, 4, 5, 2, 3, 4, 5, 3, 4, 5, 4, 5, 5) (1:5, 2:5, 3:5, 4:5, 5:5).