R programming loop

I am just starting the R program. I have couple of questions. I want to create for loop. For example; I created like this. But I want to, loop created every x value,

result = result + 2*n+1 
for x = -1 result = 0
for x = 0 result = 0
for x = 1 result = 3
for x = 2 result = 6
# etc, until
x = 9 result = 27


result = 0
vector<-c(-1:9)
for (x in vector){
  print(x)
  x = x+1
  n = as.integer(1)
  if (x<=0){
    result= 1
  } else{
    result = result + 2*n+1
  }
}
print(result)