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A085309
Initial values providing nontrivial cyclic attractor when function defined in A085307 is iterated.
4
213, 323, 639, 713
OFFSET
1,1
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
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Jun 27 2003
STATUS
approved