A118510 Define sequence S_m by: initial term = m, reverse digits and add 1 to get next term. It is conjectured that S_m always reaches a cycle of length 9, as in A117230. Sequence gives records for number of steps to reach cycle.

1, 18, 19, 36, 37, 54, 55, 72, 73

Offset: 1

Author

N. J. A. Sloane, May 06 2006

Keywords

• nonn
• base

Comments

The values of m which take this many steps are 1, 11, 101, 1001, 10001, 100001, 1000001, 10000001, 100000001, ...

Links

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

Crossrefs

Records in A118511.

Cf. A117230, A117831, A118473, A118474.

Formula

a(n) = 1 + 9*(n-1) for odd n; a(n) = 9*n for even n. Recursion: a(1) = 1; a(2) = 18; a(n+1) = a(n-1) + 18. - (Klaus Brockhaus, Jul 28 2006)

Extensions

a(5) to a(9) from Klaus Brockhaus, Jul 28 2006