Cumulating neighbours lists
You can cumulate multiple neighbour lists to a single neighbour list:
nblag_cumul(<list of neighbours lists>)
Cumulating the 1st and 2nd order neighbours lists from before:
## [1] "nb"
## [[1]]
## [1] 2 3 4 5
##
## [[2]]
## [1] 1 3 4 5 8
##
## [[3]]
## [1] 1 2 4 5 6 8 9 11 15 16
##
## [[4]]
## [1] 1 2 3 5 6 7 8 9 11 12 13 15 16
##
## [[5]]
## [1] 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 18 20 22 24 25 26
##
## [[6]]
## [1] 3 4 5 8 9 10 11 15 16 20 22 25 26