A133144 Start with n and repeatedly apply the powerback map of A133048. Sequence gives number of steps to the point where the next number would be one that has appeared before.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 4, 6, 3, 2, 1, 1, 1, 7, 3, 2, 3, 6, 3, 7, 1, 1, 2, 2, 4, 3, 3, 3, 2, 5, 1, 1, 2, 5, 2, 2, 6, 5, 4, 2, 1, 1, 3, 7, 2, 4, 4, 5, 4, 5, 1, 1, 4, 4, 5, 2, 3, 6, 4, 3, 1, 1, 4, 5, 3, 5, 5, 3, 4, 5, 1, 1, 3, 9, 4, 6, 2, 2, 5, 3

Offset

0,25

Comments

It is conjectured that every number eventually reaches a fixed point (see A131571) or the cycle of length 2 given by (175 <-> 78125).

Links

Eder Vanzei, Table of n, a(n) for n = 0..10000

Example

n, a(n), trajectory
22, 1, [22, 4]
23, 1, [23, 9]
24, 2, [24, 16, 6]
25, 0, [25]
26, 4, [26, 36, 216, 12, 2]
27, 6, [27, 49, 6561, 15625, 194400, 2304, 9]
28, 3, [28, 64, 4096, 0]
29, 2, [29, 81, 1]
30, 1, [30, 3]
31, 1, [31, 1]
32, 1, [32, 8]
33, 7, [33, 27, 49, 6561, 15625, 194400, 2304, 9]
34, 3, [34, 64, 4096, 0]
35, 2, [35, 125, 25]
36, 3, [36, 216, 12, 2]
37, 6, [37, 343, 243, 162, 64, 4096, 0]
38, 3, [38, 512, 10, 1]
39, 7, [39, 729, 567, 588245, 5242880000, 8589934592, 105911076180375000000000, 0]

Crossrefs

Sequence in context: A319931 A192133 A244109 * A342384 A192134 A322402

Adjacent sequences: A133141 A133142 A133143 * A133145 A133146 A133147

Keyword

nonn,base

Author

J. H. Conway and N. J. A. Sloane, Jan 01 2008

Status

approved