' Return the next term in the self-referential sequence
Function findNext(nStr As String) As String
    Static As Integer i, j, cnt
    Static As String outStr
    Dim As String digits(1000)
    Dim As Integer nLen = Len(nStr)

    ' Convert string to array
    For i = 1 To nLen
        digits(i-1) = Mid(nStr, i, 1)
    Next

    ' Sort digits in descending order
    For i = 0 To nLen-2
        For j = i+1 To nLen-1
            If Val(digits(i)) < Val(digits(j)) Then Swap digits(i), digits(j)
        Next
    Next

    ' Count and build output
    cnt = 1
    outStr = ""
    For i = 0 To nLen-1
        If i < nLen-1 Andalso digits(i) = digits(i+1) Then
            cnt += 1
        Else
            outStr &= Trim(Str(cnt)) & digits(i)
            cnt = 1
        End If
    Next

    Return outStr
End Function

' Return boolean indicating whether table t contains string s
Function contains(sequence() As String, term As String, seqLen As Integer) As Boolean
    For i As Integer = 0 To seqLen-1
        If sequence(i) = term Then Return True
    Next
    Return False
End Function

' Return the sequence generated by the given seed term
Sub buildSeq(seed As String, sequence() As String, Byref seqLen As Integer)
    Dim As String term = Trim(seed)
    seqLen = 0

    Do
        sequence(seqLen) = term
        seqLen += 1
        term = findNext(term)
    Loop Until contains(sequence(), term, seqLen)
End Sub

' Main program
Dim Shared As String sequences(1000, 100)
Dim As String currentSeq(100)
Static As Integer highest, seqCount, currentLen
Static As Integer i, j

highest = 0
seqCount = 0
For i = 1 To 1e6
    buildSeq(Str(i), currentSeq(), currentLen)

    If currentLen > highest Then
        highest = currentLen
        seqCount = 1
        For j = 0 To currentLen-1
            sequences(0, j) = currentSeq(j)
        Next
    Elseif currentLen = highest Then
        For j = 0 To currentLen-1
            sequences(seqCount, j) = currentSeq(j)
        Next
        seqCount += 1
    End If
Next

Print "Seed values: ";
For i = 0 To seqCount-1
    Print Trim(sequences(i, 0)); " ";
Next
Print !"\n\nIterations: "; highest
Print !"\nSample sequence:"
For i = 0 To highest-1
    Print sequences(0, i)
Next

Sleep