A073142 List of smallest solutions for some k of x = f^k(x), n <> f^j(n) for j < k, where f: m -> |m - reverse(m)|.

0, 2178, 11436678, 108811891188, 118722683079

Offset

1,2

Comments

In the definition, j can be restricted to proper divisors of k. A073143 gives the corresponding values of k. A073144(n) gives the smallest m such that the 'Reverse and Subtract' trajectory of m leads to a(n). Presumably a(6) = 1186781188132188 with k = 17.

Links

Table of n, a(n) for n=1..5.

Example

a(3) = 11436678 is the smallest solution of x = f^14(x) and there is no k such that x = f^k(x) has a smallest solution between a(2) = 2178 and a(3).

Crossrefs

Cf. A072137, A072141, A072142, A072143, A072718, A072719, A073143, A073144.

Sequence in context: A262792 A035770 A107566 * A137874 A137875 A020425

Adjacent sequences: A073139 A073140 A073141 * A073143 A073144 A073145

Keyword

base,more,nonn

Author

Klaus Brockhaus, Jul 17 2002

Extensions

Offset changed by N. J. A. Sloane, Dec 01 2007

Status

approved