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%I #5 May 26 2014 23:48:49
%S 721,708,686,709,714,656,724,756,662,721,708,695,664,732,728,715,720,
%T 707,685,708,713,655,723,755,661,15,707,712,699,686,700,732,710,0,729,
%U 1,694,654,731,709,687,710,715,657,725,757,663,722,709,714,701,688,702
%N Let S_n be the infinite sequence formed by starting with n and repeatedly reversing the digits and adding 16 to get the next term. Sequence gives number of steps for S_n to reach a cycle, or -1 if no cycle is ever reached.
%C It is conjectured that S_n always reaches a cycle.
%C There is one cycle of length 54 (least component is 34, all components have at most four digits, cf. A119454), 19 different cycles of length 90 with 4-digit components (least components are 1027 + 2*k for k = 0, ..., 18, cf. A119455), 444 different cycles of length 450 with 6-digit components, 3 different cycles of length 810 with 6-digit components (least components are 101007, 101011, 101015), 19 different cycles of length 1890 with 6-digit components (least components are 100027 + 2*k for k = 0, ..., 18) and at least 19 different cycles of length 19890 with 8-digit components (least components are 10000027 + 2*k for k = 0, ..., 18).
%H N. J. A. Sloane and others, <a href="/wiki/Sequences_of_RADD_type">Sequences of RADD type</a>, OEIS wiki.
%Y S_1 is given in A118533. Records: A119452; where records occur: A119453. Cycles of length 54 and 90 are in A119454 and A119455.
%K nonn,base
%O 1,1
%A _Klaus Brockhaus_, May 20 2006
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