A118878 Let T(S,Q) be the sequence obtaining by starting with S and repeatedly reversing the digits and adding Q to get the next term. a(n) is the number of steps for T(n,5) to reach a cycle, or -1 if no cycle is ever reached.

1, 190, 1, 87, 1, 0, 189, 0, 86, 0, 0, 188, 0, 85, 191, 0, 0, 95, 0, 190, 1, 0, 184, 0, 3, 187, 0, 0, 91, 0, 96, 0, 0, 180, 88, 0, 183, 0, 0, 87, 1, 92, 0, 0, 3, 84, 0, 179, 0, 0, 191, 0, 88, 0, 2, 190, 2, 87, 2, 1, 2, 97, 2, 192, 3, 0, 186, 0, 83, 189, 0, 0, 93, 0, 98, 0, 0, 182, 0, 1, 185, 0, 0, 89, 3, 94, 0, 0, 178, 86, 0, 181, 0, 0, 193, 0, 90, 0, 0, 1

Offset: 1

Author

N. J. A. Sloane, May 26 2006

Keywords

• nonn
• base

Comments

Is a(n) ever -1? If so then n > 10000.

The cycle has length 207 for S <= 1015, but for S = 1016 it has length 36 (see A118879).

Links

• N. J. A. Sloane and others, Sequences of RADD type, OEIS wiki.

Crossrefs

Cf. A117828, A117800, A118879.