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Search: id:A071848
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| A071848 |
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a(n) = smallest positive integer that cannot be obtained using the number n exactly n times and the operations +, -, *, /, where intermediate subexpressions must be integers. |
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+0
1
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| 2, 3, 5, 10, 13, 22, 38, 85, 138, 246, 547, 1121, 2792, 3967, 12756
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Joe Crump's page indicates that a(9) = 195 if noninteger subexpressions are permitted. - David W. Wilson, Jan 14 2007
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LINKS
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G. Bannay, LE COMPTE EST BON
Joe Crump, The Nine 9s
Index entries for similar sequences
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EXAMPLE
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a(3)=5 because using 3 at most thrice we can have 3/3=1, 3-(3/3)=2, 3=3, 3+(3/3)=4 but we cannot obtain 5 this way.
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CROSSREFS
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Cf. A060315.
Sequence in context: A162404 A084760 A103746 this_sequence A120938 A120610 A090859
Adjacent sequences: A071845 A071846 A071847 this_sequence A071849 A071850 A071851
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KEYWORD
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hard,more,nonn
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AUTHOR
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Koksal Karakus (karakusk(AT)hotmail.com), Jun 09 2002
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EXTENSIONS
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Definition corrected by David W. Wilson, Jan 14 2007
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