Dear Math Fun: A correspondent from Belgium, Luc Stevens suggested looking at the sequences that I now call RADD sequences (not to be confused with the old RATS, Reverse, Add Then Sort sequences): T(S,Q) is formed by starting with S; to get later terms, reverse previous term annd add Q. (Of course leading zeros are omitted.) For a summary of these sequences, see my article "Sequences of RADD type" that is linked to A117831. This gives a lot of data, including many references to new entries in the OEIS. Example: T(1,1) is 1,2,3,4,5,6,7,8,9,10,2,3,4,5,6,7,... (A117230) which reaches a cycle of length 9 in 1 step. But T(1,10) never cycles (A117841). My question is, has anyone seen any previous work on these sequences? How can they possibly be new? Surely someone must have determined which ones cycle and which do not? Can anyone supply references? Neil