[seqfan] Re: A permutation with divisions

[Eric Angelini]

Oh yes... geee, Andrew, sorry...
After 20 should come 21, of course...

Catapulté de mon aPhone

> Le 25 janv. 2014 à 11:06, "Andrew Weimholt" <andrew.weimholt at gmail.com> a écrit :
> 
> 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
> 
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