为什么我无法在R中创建序列？

Question

这是我生成数字序列的代码。序列从3开始，并在用户输入的数字的sqaure根处停止。

num = as.numeric(readline(prompt = "Enter a number :"))
mysqrt = as.integer(sqrt(num))
myseq = seq(from = 3,to = mysqrt, by = 2)

我得到的错误是 - ＆gt;

Error in seq.default(from = 3, to = mysqrt, by = 2) : 
  wrong sign in 'by' argument

如果我跑 - ＆gt;

seq(3,as.integer(sqrt(25)), by = 2)

它按预期正常工作。

如果我跑 - ＆gt;

num = 25
seq(3,as.integer(sqrt(num)), by = 2)

它给出了上述错误。