Revision History for A117817
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A117817
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Let T_n be the infinite sequence formed by starting with 1 and repeatedly reversing the digits and adding n to get the next term. If T_n eventually reaches a cycle, sequence gives length of that cycle, otherwise -1.
(history;
published version)
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#8 by N. J. A. Sloane at Mon May 26 23:48:47 EDT 2014
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N. J. A. Sloane and others, <a href="/A117831wiki/a117831.txtSequences_of_RADD_type">Sequences of RADD type</a>>, OEIS wiki.
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Discussion
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Mon May 26
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#7 by N. J. A. Sloane at Thu Apr 03 11:35:06 EDT 2014
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a(multiple of 10) = -1 (see A117816). a(15) = -1 (see A118532). a(n) is a multiple of 9/gcd(9,n) unless it is -1. - . - _Martin Fuller (martin_n_fuller(AT)btinternet.com), _, May 12 2006
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| EXTENSIONS
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a(33) onwards from T. D. Noe and _Martin Fuller (martin_n_fuller(AT)btinternet.com), _, May 10 2006
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Discussion
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Thu Apr 03
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#6 by Russ Cox at Fri Mar 30 17:22:42 EDT 2012
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| EXTENSIONS
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a(33) onwards from _T. D. Noe (noe(AT)sspectra.com) _ and Martin Fuller (martin_n_fuller(AT)btinternet.com), May 10 2006
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Discussion
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Fri Mar 30
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| OEIS Server: https://oeis.org/edit/global/120
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#5 by Russ Cox at Fri Mar 30 16:50:25 EDT 2012
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| AUTHOR
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_N. J. A. Sloane (njas(AT)research.att.com), _, following discussions with Luc Stevens, May 04 2006
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Discussion
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Fri Mar 30
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| OEIS Server: https://oeis.org/edit/global/110
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#4 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010
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| LINKS
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N. J. A. Sloane, <a href="="/A117831/a117831.txt">Sequences of RADD type</a>
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| KEYWORD
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sign,base,new
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#3 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009
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| LINKS
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N. J. A. Sloane, <a href="http://www.research.att.com/~njas/sequences/a117831.txt">Sequences of RADD type</a>
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| KEYWORD
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sign,base,new
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| AUTHOR
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N. J. A. Sloane (njas, (AT)research.att.com), following discussions with Luc Stevens, May 04 2006
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#2 by N. J. A. Sloane at Fri Sep 29 03:00:00 EDT 2006
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| DATA
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9, 81, 3, 54, 207, 30, 63, 27, 1, -1, 9, 15, 18, 72, -1, 90, 54, 13, 18, -1, 15, 9, 9, 36, 45, 18, 9, 36, 18, -1, 9, 9, 3, 36, 72, 2, 27, 18, 3, -1, 18, 57, 63, 9, 22, 90, 18, 30, 54, -1, 6, 99, 54, 13, 36, 207, 12, 63, 45, -1, 36, 27, 30, 108, 36, 264, 99, 36, 3, -1, 18, 22, 45, 90, 12, 45, 117, 192, 18, -1, 36, 45, 63, 168, 1008, 36, 24, 306, 9, -1, 99, 639, 36, 54, 144, 18, 225, 468, 1, -1, 18, 300, 189, 171, 765, 90, 45, 462, 90, -1, 9, 513, 63, 69
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| COMMENTS
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Fora(multiple of 10) = -1 (see A117816). a(15) = -1 (see A118532). a(n) is a discussionmultiple of 9/gcd(9,n) unless it theis -1. - Martin entriesFuller (martin_n_fuller(AT)btinternet.com), May see12 A117817.2006
For a discussion of the -1 entries see A117816.
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| KEYWORD
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nonnsign,base,new
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#1 by N. J. A. Sloane at Fri May 19 03:00:00 EDT 2006
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| NAME
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Let T_n be the infinite sequence formed by starting with 1 and repeatedly reversing the digits and adding n to get the next term. If T_n eventually reaches a cycle, sequence gives length of that cycle, otherwise -1.
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| DATA
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9, 81, 3, 54, 207, 30, 63, 27, 1, -1, 9, 15, 18, 72, -1, 90, 54, 13, 18, -1, 15, 9, 9, 36, 45, 18, 9, 36, 18, -1, 9, 9, 3, 36, 72, 2, 27, 18, 3, -1, 18, 57, 63, 9, 22, 90, 18, 30, 54, -1, 6, 99, 54, 13, 36, 207, 12, 63, 45, -1, 36, 27, 30, 108, 36, 264, 99, 36, 3, -1, 18, 22, 45, 90, 12, 45, 117, 192, 18, -1, 36, 45, 63, 168, 1008, 36, 24
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| OFFSET
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1,1
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| COMMENTS
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For a discussion of the -1 entries see A117817.
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| LINKS
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N. J. A. Sloane, <a href="http://www.research.att.com/~njas/sequences/a117831.txt">Sequences of RADD type</a>
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| MATHEMATICA
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ReverseNum[n_] := FromDigits[Reverse[IntegerDigits[n]]]; maxLen=10000; Table[z=1; lst={1}; While[z=ReverseNum[z]+n; !MemberQ[lst, z] && Length[lst]<maxLen, AppendTo[lst, z]]; If[Length[lst]<maxLen, Length[lst]-Position[lst, z][[1, 1]]+1, -1], {n, 100}] (Noe)
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| CROSSREFS
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See A117817 for the -1 entries and cross-references to T_1 through T_16.
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| KEYWORD
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nonn,base,new
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| AUTHOR
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njas, following discussions with Luc Stevens, May 04 2006
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| EXTENSIONS
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a(21)-a(33) from Luc Stevens, May 08 2006
a(33) onwards from T. D. Noe (noe(AT)sspectra.com) and Martin Fuller (martin_n_fuller(AT)btinternet.com), May 10 2006
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| STATUS
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approved
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