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Search: id:A141842
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| A141842 |
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a(n) = first term that can be reduced in n steps via repeated interpretation of a(n) as a base b+1 number where b is the largest digit of a(n), such that b is always 8 so that each interpretation is base 9. Terms already fully reduced (i.e. single digits) are excluded. |
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+0
7
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| 18, 86, 680, 835, 7087, 12788, 18478, 128117, 385732, 2206280, 13176873, 33185141, 68388408, 335213686, 1365888758
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is sometimes possible to compute additional terms by taking the last term, treating it as base 10 and converting to base 9. This may create a term minimally interprettable as base 9 which can converted back to base 10 yielding the previous term in the sequence which will itself yield N further terms. But there is no guarantee (except in base 2) that the term so derived will be the first term to produce a sequence of N+1 terms. There could be another, smaller, term which satisfies that requirement but which uses different terms. Pushing the last term of this sequence does not produce a value minimally interprettable as base 9.
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EXAMPLE
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a(3) = 680 because 680 is the first number that can produce a sequence of three terms by repeated interpetation as a base 9 number: [680] (base-9) --> [558] (base-9) --> [458] (base-9) --> [377]. Since 377 cannot be minimally interpretted as a base 9 number, the sequence terminates with 458. a(1) = 18 because 18 is the first number that can be reduced once, yielding no further terms minimally interprettable as base 9.
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CROSSREFS
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Cf. A091049, A141836, A141837, A141838, A141839, A141840, A141841.
Sequence in context: A067984 A124935 A126405 this_sequence A063788 A066854 A059138
Adjacent sequences: A141839 A141840 A141841 this_sequence A141843 A141844 A141845
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KEYWORD
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base,more,nonn
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AUTHOR
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Chuck Seggelin (seqfan(AT)plastereddragon.com), Jul 10 2008
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