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Search: id:A072138
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| A072138 |
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Smallest k whose 'Reverse and Subtract' trajectory has a preperiodic part of length n. |
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+0
3
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| 0, 1, 10, 16, 14, 15, 13, 1011, 1017, 1037, 1027, 1014, 1013, 1028, 100113, 100104, 100145, 100134, 100103, 100112, 100133, 100187, 100114, 100128, 100194, 100107, 100307, 100277, 100413, 100345, 100429, 100215, 100427, 100214, 100433, 100335
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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'Reverse and Subtract' (cf. A072137) is defined by x -> |x - reverse(x)|. For small n the last term of the preperiodic part of the trajectory (cf. A072139) is a palindrome, so this sequence is a weak analogue of A033665, which uses 'Reverse and Add'. - 1012 is the first n such that last term of the preperiodic part is not palindromic (cf. A072140).
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EXAMPLE
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a(8) = 1017, since 1017 is the smallest number whose 'Reverse and Subtract' trajectory has eight preperiodic terms: 1017 -> 6084 -> 1278 -> 7443 -> 3996 -> 2997 -> 4995 -> 999.
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CROSSREFS
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Cf. A033665, A072137, A072139, A072140, A072146.
Sequence in context: A114703 A134515 A072968 this_sequence A109891 A104869 A104868
Adjacent sequences: A072135 A072136 A072137 this_sequence A072139 A072140 A072141
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KEYWORD
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base,nonn
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AUTHOR
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Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 24 2002
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