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Search: id:A047985
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| A047985 |
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Define value of a number m (A047988) as follows: start with m and reach 2 by repeatedly either dividing by d where d <= the square root or by adding or subtracting 1. The division steps are free, but adding or subtracting 1 costs 1 point. The "value" of m is the smallest cost to reach 2. Sequence gives numbers with value 2. |
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+0
3
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| 19, 29, 38, 43, 53, 58, 67, 76, 86, 87, 89, 101, 103, 106, 116, 134, 137, 139, 149, 151, 152, 157, 163, 172, 174, 178, 197, 202, 203, 206, 211, 212, 227, 229, 232, 233, 247, 261, 267, 268, 269, 271, 274, 277, 278, 283, 293, 298, 302, 303, 304, 307
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Thomas Kantke, Mathematische Unterhaltungen, Spectrum der Wissenschaft, April 1993, pp. 11-13.
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EXAMPLE
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19 has value 2 since by adding 1 we reach 20 which has value 1; there is no cheaper way to reach 2.
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CROSSREFS
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Cf. A047836, A047984, A047986-A047988.
Sequence in context: A140566 A135170 A139539 this_sequence A061763 A088474 A087097
Adjacent sequences: A047982 A047983 A047984 this_sequence A047986 A047987 A047988
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KEYWORD
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nonn
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AUTHOR
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Thomas Kantke (bytes.more(AT)ibm.net)
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EXTENSIONS
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More terms from David W. Wilson (davidwwilson(AT)comcast.net)
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