VB编写杨辉三角?

Option Explicit
Private Sub Form_Click()
Dim i As Integer, j As Integer, n As Integer, b As Integer, c As Integer
ReDim a(b, c) As Integer
n = InputBox("请输入n:")
If i + j = n + 1 Or j = n + 1 + i Then
a(i, j) = 1
a(0, n + 1) = 1
Else
For i = 2 To n Step 1
For j = n + 3 - i To n - 1 + i Step 2
a(i, j) = a(i - 1, j - 1) + a(i - 1, j + 1)
Next j
Print
Next i
End If
End Sub

这么编写为什么出错?
为什么a(i, j) = a(i - 1, j - 1) + a(i - 1, j + 1)总说下表越界?
那该怎么写呢

vb编写杨灰三角 vb 杨辉三角 java编写杨辉三角~~~ c语言编写杨辉三角 怎么用fortran编写杨辉三角 怎样用c语言编写杨辉三角 VB编程打印输出杨辉三角? 杨辉三角VB设计程序 vb杨辉三角 等腰用label 用c语言如何编写杨辉三角