A209879 RATS: Reverse Add Then Sort the digits applied to previous term, starting with 6999.

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

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