' FB 1.05.0 Win64

Function isHappy(n As Integer) As Boolean
  If n < 0 Then Return False
  ' Declare a dynamic array to store previous sums.
  ' If a previous sum is duplicated before a sum of 1 is reached
  ' then the number can't be "happy" as the cycle will just repeat
  Dim prevSums() As Integer
  Dim As Integer digit, ub, sum = 0
  Do
    While n > 0
      digit = n Mod 10
      sum += digit * digit
      n \= 10
    Wend
    If sum = 1 Then Return True
    ub = UBound(prevSums)
    If ub > -1 Then
      For i As Integer = 0 To ub
         If sum = prevSums(i) Then Return False
      Next
    End If
    ub += 1
    Redim Preserve prevSums(0 To ub)
    prevSums(ub) = sum
    n = sum
    sum  = 0
  Loop
End Function

Dim As Integer n = 1, count = 0

Print "The first 8 happy numbers are : "
Print
While count < 8
  If isHappy(n) Then
    count += 1
    Print count;" =>"; n
  End If
  n += 1
Wend
Print
Print "Press any key to quit"
Sleep