# Custom function don't read vectors

I have this custom function to show the combinations:

x<-function(a,b){

ncol(combn(a,b))

}

combinations<-numeric()

for(i in 0:12){
combinations<-c(combinations,x(12,i))
}

combinations


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

x<-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)