[seqfan] Re: List the dividers, sum the digits

[M. F. Hasler]

Eric,

I found that this is  A094501.
I did not find at once this and
A086793 = Iterate the map n -> sum of digits of all divisors of n (cf.
A034690); sequence gives number of steps to reach 15.
because I considered the version "...to reach a fixed point (1 or 15)"
which starts with 1.
I hope it will be accepted to change A086793 in order to prefix a(1)=1.

Maximilian


On Sun, Nov 8, 2015 at 1:11 PM, Eric Angelini <Eric.Angelini at kntv.be> wrote:
>
> Hello SeqFans,
> Jean-Marc Falcoz has computed the
> 22 first terms of the A(n) seq where
> a(1) is the smallest integer looping in
> 1 stage, a(2) the smallest looping in
> 2 stages, a(3) in 3 stages, etc.
> It seems that computing a(23) will
> take a lot of time [the graph of A(n)
> climbs exponentially after a(22)] --
> not to say a(24)]. If someone wants
> to give it a try and submit the seq to
> the OEIS, please do...
> Best,
> É.
>
> {1},
> {8, 15},
> {7, 8, 15},
> {4, 7, 8, 15},
> {3, 4, 7, 8, 15},
> {2, 3, 4, 7, 8, 15},
> {19, 11, 3, 4, 7, 8, 15},
> {12, 19, 11, 3, 4, 7, 8, 15},
> {6, 12, 19, 11, 3, 4, 7, 8, 15},
> {5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {10, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {16, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {34, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {66, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {162, 66, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {924, 168, 102, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15},
> {71820, 1104, 168, 102, 36, 46, 18, 30, 27, 22, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15}