[seqfan] Re: The a(n)th digit of the sequence is visible in a(n).

Eric Angelini Eric.Angelini at kntv.be
Sat Sep 27 17:35:00 CEST 2014


Maximilian I like your code a lot! 
It correctly spotted my mistaken 99!
Best and congratulations !
É.

Catapulté de mon aPhone

> Le 27 sept. 2014 à 16:08, "M. F. Hasler" <oeis at hasler.fr> a écrit :
> 
> Hello Eric, Seqfans,
> 
> sorry for forgetting about the must-be-permutation constraint in my earlier
> remark...
> Now I wrote a PARI 2-3-liner to compute the sequence, but it differs
> slightly from yours (starting with an 89 instead of your 99 preceding
> 10,20...)
> My code is so simple that it's probable I forgot something, but I don't
> know what it could be. (To be honest, I did not think about it very long
> (*shame*)...)
> Here's what I get for S(1..100):
> 
> S=1,2,3,4,5,6,7,8,9,11,13,15,17,19,21,22,25,27,29,31,23,33,37,39,41,24,44,47,49,51,53,45,55,59,61,26,46,66,69,71,73,75,67,77,81,28,48,
> 68,88,91,93,95,97,89,10,20,40,60,80,111,14,16,18,12,112,42,62,82,113,34,36,38,30,114,116,74,90,52,35,56,58,50,121,65,118,101,117,57,
> 78,70,123,85,87,110,92,94,96,79,100,200,...
> 
> (PARI)
> EA(nMax,d=[],u=0)={for(n=1,nMax,for(k=1,9e9,bittest(u,k)&&next;
> for(j=1,#dk=digits(k),setsearch(Set(digits(#d+j)),dk[j])||next(2));
> d=concat(d,digits(k));u+=1<<k;print1(k",");next(2));error)}
> 
> Best,
> M.
> 
> On Thu, Sep 25, 2014 at 5:37 PM, Eric Angelini <Eric.Angelini at kntv.be>
> wrote:
> 
>> 
>> Hello SeqFans,
>> 
>> 
>> S=1,2,3,4,5,6,7,8,9,11,13,15,17,19,21,22,25,27,29,31,23,33,37,39,41,24,44,47,49,51,53,45,55,59,61,26,46,66,69,71,73,75,67,77,81,28,48,68,88,91,93,95,97,99,10,20,40,60,80,111,14,16,18,12,112,42,62,82,113,34,36,38,30,114,116,74,90,52,35,56,58,50,121,65,118,117,115,57,78,70,123,85,87,89,119,94,96,79,92,100,...
>> 
>> This is the lexico-first permutation of
>> the integers > 0 such that the a(n)th
>> digit of the sequence is visible in a(n).
>> 
>> Example (read from the present end of S):
>> - the 100st digit of S is 1
>> - the 92nd digit of S is 9
>> - the 79th digit of S is 7
>> - the 96th digit of S is 9, etc.
>> 
>> Best,
>> É.
> 
> _______________________________________________
> 
> Seqfan Mailing list - http://list.seqfan.eu/


More information about the SeqFan mailing list