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 A209880 RATS: Reverse Add Then Sort the digits applied to previous term, starting with 29. 7
 29, 112, 233, 556, 1112, 2233, 5555, 1111, 2222, 4444, 8888, 16777, 34589, 112333, 444455, 889999, 1788899, 1177777, 4558889, 13444447, 77888888, 156667777, 233444489, 1112278888, 11999, 11119, 1223, 4444, 8888, 16777, 34589, 112333, 444455, 889999, 1788899 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A114616(1) = 29 is the smallest starting number for a RATS trajectory leading to a cycle of length 18: A114611(29) = 18; a(n + 18) = a(n) for n > 9. LINKS Eric Weisstein's World of Mathematics, RATS Sequence Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1). FORMULA a(n + 1) = A036839(a(n)). MATHEMATICA NestList[FromDigits[Sort[IntegerDigits[#+IntegerReverse[#]]]]&, 29, 40] (* or *) PadRight[{29, 112, 233, 556, 1112, 2233, 5555, 1111, 2222}, 50, {4558889, 13444447, 77888888, 156667777, 233444489, 1112278888, 11999, 11119, 1223, 4444, 8888, 16777, 34589, 112333, 444455, 889999, 1788899, 1177777}] (* Harvey P. Dale, Sep 17 2018 *) PROG (Haskell) a209880 n = a209880_list !! (n-1) a209880_list = iterate a036839 29 CROSSREFS Cf. A004000, A066710, A209878, A066711, A209879. Sequence in context: A232787 A232852 A233117 * A232784 A232849 A233118 Adjacent sequences:  A209877 A209878 A209879 * A209881 A209882 A209883 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Mar 14 2012 STATUS approved

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Last modified August 15 19:11 EDT 2022. Contains 356148 sequences. (Running on oeis4.)