Creating higher order neighbours lists

lapply(nblags, head, 2)

## [[1]]
## [[1]][[1]]
## [1] 2 3
## 
## [[1]][[2]]
## [1] 1 3 4
## 
## 
## [[2]]
## [[2]][[1]]
## [1] 4 5
## 
## [[2]][[2]]
## [1] 5 8
## 
## 
## [[3]]
## [[3]][[1]]
## [1]  6  8  9 11 15 16
## 
## [[3]][[2]]
## [1]  6  7  9 11 12 13 15 16