

A117817


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.


72



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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OFFSET

1,1


COMMENTS

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, May 12 2006
For a discussion of the 1 entries see A117816.


LINKS

Table of n, a(n) for n=1..114.
N. J. A. Sloane and others, Sequences of RADD type, OEIS wiki.


MATHEMATICA

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)


CROSSREFS

See A117817 for the 1 entries and crossreferences to T_1 through T_16.
Sequence in context: A143848 A317052 A332702 * A328760 A228591 A219664
Adjacent sequences: A117814 A117815 A117816 * A117818 A117819 A117820


KEYWORD

sign,base


AUTHOR

N. J. A. Sloane, following discussions with Luc Stevens, May 04 2006


EXTENSIONS

a(21)a(33) from Luc Stevens, May 08 2006
a(33) onwards from T. D. Noe and Martin Fuller, May 10 2006


STATUS

approved



