VB递归函数的问题

Private Sub Command1_Click()
Dim a1 As Long
Dim a, x As Double
n = InputBox("输入一个正整数n=")
x = InputBox("再输入一个数X=")
a = 0
For i = 1 To n
a1 = 1
For j = 1 To 2 * i - 1
a1 = a1 * j
Next
a = a + x ^ (2 * i - 1) / a1
Next
Print Tab(1); a1; Tab(10); a;
End Sub

Private Sub Form_Click()
Dim x As Single, s As Double, i As Integer
Dim j As Double, k As Double
x = InputBox("请输入x")
n = InputBox("请输入n")
For i = 1 To 2 * n - 1 Step 2
k = 1
For j = i To 2 * n - 1
k = k * j
Next j
s = s + x ^ i / k
Next i
Print s
End Sub