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A123895
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Restricted growth string for the (decimal expansion of the) number n.
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3
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0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 11, 12, 12, 12, 12, 12, 12, 12, 12, 10, 12, 11, 12, 12, 12, 12, 12, 12, 12, 10, 12, 12, 11, 12, 12, 12, 12, 12, 12, 10, 12, 12, 12, 11, 12, 12, 12, 12, 12, 10, 12, 12, 12, 12, 11, 12, 12, 12, 12, 10, 12, 12, 12, 12, 12, 11, 12, 12
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,11
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COMMENTS
| Write n in base 10 prefixed with a 0. Read this string from left to right. Write a 0 each time you see the first distinct digit (which is 0), write a 1 each time you see the second distinct digit, write a 2 each time you see the third distinct digit and so on. Finally, delete the leading zeros.
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REFERENCES
| D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.5, p. 432, Problems 4 and 5.
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EXAMPLE
| To find a(66041171): 066041171 -> 011023343 -> 11023343.
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PROG
| (VBA program from Franklin T. Adams-Watters)
Public Function RestrictedGrowthString(ByVal x As String) As String
Dim i As Long
Dim dig As Integer
Dim pos As Long
For i = 1 To Len(x)
If Mid(x, i, 1) = "0" Then
RestrictedGrowthString = RestrictedGrowthString & "0"
Else
pos = InStr(x, Mid(x, i, 1))
If pos = i Then
dig = dig + 1
RestrictedGrowthString = RestrictedGrowthString &
Format(dig)
Else
RestrictedGrowthString = RestrictedGrowthString &
Mid(RestrictedGrowthString, pos, 1)
End If
End If
Next i
End Function
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CROSSREFS
| Cf. A123896, A123902.
Sequence in context: A063671 A184992 A162501 * A147519 A100830 A180176
Adjacent sequences: A123892 A123893 A123894 * A123896 A123897 A123898
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KEYWORD
| nonn,base
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Nov 20 2006
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