A175425 The smallest number m which needs n iterations of the map x->A175420(x) to reach a single-digit number.

0, 10, 24, 27, 33

Offset

0,2

Comments

Conjecture: sequence a(n) is finite for n = natural number, a(n) = 25 for n = infinity. See A175424.

Links

Table of n, a(n) for n=0..4.

Formula

a(n) = min {j : A175425(j) = n}.

Example

a(4) = 33 because 33 is the smallest numbers with 4 steps of defined iteration: 3^3 = 27, 7^2 = 49, 9^4 = 6561, ((1^6)^5)^6 = 1.

Crossrefs

Cf. A175419 - A175427.

Sequence in context: A187629 A175403 A133503 * A076675 A063925 A101156

Adjacent sequences: A175422 A175423 A175424 * A175426 A175427 A175428

Keyword

nonn,base

Author

Jaroslav Krizek, May 09 2010

Status

approved