foo <- function(n, s = NULL, t = NULL, f = NULL){

   d <- if(!is.null(t)) t + n else if(!is.null(f)) f^2 + n

  m <- if(!is.null(s)) s/2 else NULL
  r <- if(!is.null(m)) m + 1 else NULL

  if(!is.null(m) & is.null(m)) d <- m + r

  out <- data.frame(d)
  rownames(out) <- paste0("BB", 1:length(d))
  out
  }
 # Example of use:
 foo(n = 30:35, s = 1:2, t = 3:5, f = 7)

## OUTPUT:
      d
BB1  33 # add "t" to the rownames of `d`s computed from "t" or "f" for ds computed from "f"
BB2  35
BB3  37
BB4  36
BB5  38
BB6  40