Custom function don't read vectors I have this custom function to show the combinations:

x&lt;-function(a,b){

  ncol(combn(a,b))

}

combinations&lt;-numeric()

for(i in 0:12){
    combinations&lt;-c(combinations,x(12,i))
}

combinations


It works, but I want to know if it's possible to do something simpler, like this:

x&lt;-function(a,b){

  ncol(combn(a,b))

}

x(12,0:12)
The number of combinations of size k from a set of size n can be computed with choose(n, k) in R, and if you have multiple k values you can just pass in a vector for k. Therefore your code can be simplified to:

choose(12, 0:12)
#  [1]   1  12  66 220 495 792 924 792 495 220  66  12   1