Using Arrays With IF-THEN Statements in VBA

Hello,

I'm trying to write a macro to copy a cell if the first three integers in the adjacent cell are present in an array. I'm brand new to the concept of arrays, and having a difficult time trying to figure out how to proceed. When I run the code below, I get a Type Mismatch error. I've uploaded an example of the worksheet I'm using.

Sub mcrFinancialCodeTemplates1()

Dim aryAMPTH() As Integer
Dim aryBUs As Integer
Dim i As Integer

aryBUs = "180, 181, 182, 184, 185, 751, 752, 753, 754, 755, 757, 758, 759, 762, 765, 766, 771, 773, 774, 776, 777, 810, 811, 813, 817, 818, 818, 819, 820, 822, 825, 831, 833, 834, 835, 838, 839, 950, 951, 952, 953, 954, 955, 956, 957, 959, 960, 962, 963, 964, 965, 967, 968, 969, 970, 971, 974, 975, 976, 977"
aryAMPTH = Split(aryBUs, ", ")

For i = LBound(aryAMPTH) To UBound(aryAMPTH)

Sheets("Main").Select
Range("A1").Activate
Do While Not IsEmpty(ActiveCell.Value)
If (Left(ActiveCell, 3) = aryAMPTH) Then
ActiveCell.Offset(0, 1).Copy
Sheets("Sheet1").Select
ActiveSheet.Paste
ActiveCell.Offset(0, -2) = "AMPTH"

Any help would be appreciated!