A085309 Initial values providing nontrivial cyclic attractor when function defined in A085307 is iterated.

213, 323, 639, 713

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Formula

Algorithm: 1# factorize n; 2# arrange prime-factors by decreasing size; 3# concatenate prime factors and interpret the result as decimal number.Iterate 1#, 2#, 3#.

Example

n=213 gives {213,713,3123,3473,15123,713},
n=323 gives {323,1917,713,3123,3473,15123,713},
n=639 gives {639,713,3123,3473,15123,713}.

Crossrefs

Cf. A084317-A084319, A085307, A085308, A085309.

Sequence in context: A252025 A238019 A251146 * A252024 A302256 A092127

Adjacent sequences: A085306 A085307 A085308 * A085310 A085311 A085312

Keyword

base,nonn

Author

Labos Elemer, Jun 27 2003

Status

approved