|
%I #15 Jan 02 2023 12:30:51
%S 1,8,7,4,3,2,19,12,6,5,13,9,10,16,30,18,34,36,66,162,924,71820
%N Least number such that exactly n iterations of A034690 are required to reach one of the fixed points, 1 or 15.
%C Apart from the initial term a(1), the same as A094501.
%H E. Angelini et al., <a href="http://list.seqfan.eu/oldermail/seqfan/2015-November/015585.html">List the dividers, sum the digits</a>, SeqFan list, Nov. 2015
%e The orbits are:
%e {1},
%e {8, 15},
%e {7, 8, 15},
%e {4, 7, 8, 15},
%e {3, 4, 7, 8, 15},
%e {2, 3, 4, 7, 8, 15},
%e {19, 11, 3, 4, 7, 8, 15},
%e {12, 19, 11, 3, 4, 7, 8, 15},
%e {6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {10, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {16, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {34, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {66, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {162, 66, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {924, 168, 102, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
%e {71820, 1104, 168, 102, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15}
%o (PARI) a(n)=for(k=1,9e9, A086793(k)==n&&return(k))
%Y Cf. A034690, A086793, A094501, A095347.
%K nonn,base
%O 0,2
%A _M. F. Hasler_, Nov 08 2015
|
