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 A209879 RATS: Reverse Add Then Sort the digits applied to previous term, starting with 6999. 7
 6999, 15699, 11355, 66666, 123333, 445566, 111111, 222222, 444444, 888888, 1677777, 3455589, 11112333, 33444444, 77778888, 156666666, 123333378, 666669999, 1356666666, 123333789, 11111667, 22777788, 11115555, 66666666, 123333333, 445566666, 111122223 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A114615(1) = 6999 is the smallest starting number for a RATS trajectory leading to a cycle of length 14: A114611(6999) = 14; a(n + 14) = a(n) for n > 25. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..100 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, 1). FORMULA a(n + 1) = A036839(a(n)). MATHEMATICA rats[n_]:=Module[{idnr=FromDigits[Reverse[IntegerDigits[n]]]}, FromDigits[ Sort[ IntegerDigits[idnr+n]]]]; NestList[rats, 6999, 30] (* Harvey P. Dale, May 29 2014 *) PROG (Haskell) a209879 n = a209879_list !! (n-1) a209879_list = iterate a036839 6999 CROSSREFS Cf. A004000, A066710, A209878, A066711, A209880. Sequence in context: A050673 A050663 A114615 * A100897 A206757 A236061 Adjacent sequences:  A209876 A209877 A209878 * A209880 A209881 A209882 KEYWORD nonn,base AUTHOR Reinhard Zumkeller, Mar 14 2012 STATUS approved

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Last modified December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)