[seqfan] Re: A permutation with divisions

[Andrew Weimholt]

On Sat, Jan 25, 2014 at 1:14 AM, Eric Angelini <Eric.Angelini at kntv.be>
 wrote:

>
> Hello SeqFans,
> I guess this is a nice little permutation
> of the Naturals:
>  a(1)=1
>  a(n+1) is the smallest unused integer
>  that starts with a digit dividing a(n).
>
> S=1,10,2,11,12,3,13,14,7,15,5,16,4,17,18,9,19,100,20,101,102...
>

After 20 should come 21...
By hand I get

1, 10, 2, 11, 12, 3, 13, 14, 7, 15, 5, 16, 4, 17, 18, 6, 19, 100, 20, 21,

30, 22, 23, 101, 102, 24, 8, 25, 50, 26, 27, 9, 31, 103, 104, 28, 29, 105,

32, 40, 41, 106, 107, 108, 33, 34, 109, 110, 51, 35, 52, 42, 36, 37, 111,

38, 112, 43, 113, 114, 39, 115, 53, 116, 44, 45, 54, 60, 46, 117, 90, 55,

56, 47, 118, 119, 70, 57, 120, 48, 49, 71, 121, 122, 123, 124, 125, 58,

Note: "by hand" = "warning - there may be errors"

inverse permutation (again by hand) is...

1, 3, 6, 13, 11, 16, 9, 27, 32, 2, 4, 5, 7, 8, 10, 12, 14, 15, 17, 19, 20...


Andrew