[seqfan] Re: Starting and Ending Digits

[Dmitry Kamenetsky]

On a similar note I found A067581. Can someone explain the difference
between A067581 and A098786?

Dmitry

f.firoozbakht at sci.ui.ac.ir wrote:
> 
>> I'm considering submitting (done by hand, so there may be errors):
> 
>> a(n+1) is the smallest number not yet in the sequence which contains
>> the last digit of a(n):
>>
>> 1,10,20,30,40,50,60,70,80,90,100,101,11,12,2,
>> 21,13,3,31,14,4,41,15,5,51,16,6,61,17,7,71,18,
>> 8,81,19,9,91,102,22,23,32,24,42,25,52,26,62,
>> 27,72,28,82,29,92,112,120,103,33,34,43,35,53,
>> 36,63,37,73,38,83,39,93,113,123,130,104,44,
>> 45,54,46,64,47,74,48,84,49,94,114,124,134,
>> 140,105,55,56,65,57,75,58,85,59,95,115,125,
>> 135,145,150,106,66,67,76,68,86,69,96,116,
>> 126,136,146,156,160,107,77,78,87,79,97,117,
>> 127,137,147,157,167,170,108,88,89,98,118,
>> 128,138,148,158,168,178,180,109,99,119,129,
>> 139,149,159,169,179,189,190,110,200,201,
>> 111,112,121,113,131,...
> 
>   Some of the 161 first terms which were written aren't correct.
>   The Mathematica coding for this sequence is:
> 
>    a[1]=1;a[n_]:=a[n]=(b=Table[a[k],{k,n-1}];
>    For[m=1,MemberQ[b,m]||MemberQ[IntegerDigits[m],Mod[a[n-1],10]],m++];m);
>    Table[a[t],{t,161}]
> 
>   So the first 161 terms of the sequence are:
> 
>     1,10,20,30,40,50,60,70,80,90,100,101,11,12,2,
>     21,13,3,23,31,14,4,24,34,41,15,5,25,35,45,51,
>     16,6,26,36,46,56,61,17,7,27,37,47,57,67,71,18,
>     8,28,38,48,58,68,78,81,19,9,29,39,49,59,69,79,
>     89,91,102,22,32,42,52,62,72,82,92,112,120,103,
>     33,43,53,63,73,83,93,113,123,130,104,44,54,64,
>     74,84,94,114,124,134,140,105,55,65,75,85,95,
>     115,125,135,145,150,106,66,76,86,96,116,126,
>     136,146,156,160,107,77,87,97,117,127,137,147,
>     157,167,170,108,88,98,118,128,138,148,158,168,
>     178,180,109,99,119,129,139,149,59,169,179,189,
>     190,110,200,201,111,121,122,132,142
> 
> 
>   Farideh Firoozbakht
> 
> 
> 
> Quoting franktaw at netscape.net:
> 
>> It appears to me that A125887 is an erroneous version of A076654.  I
>> would recommend marking it as "dead" rather than removing it, because
>> this is a very easy mistake to make -- I made it myself, then noticed
>> the error.  (Alternatively, the definition could be modified to require
>> the next term to have more than one digit; but then the initial 1 is an
>> anomaly.)
>>
>> A125886 is similarly erroneous.  In this case, I don't find the correct
>> version of the sequence in the database.
>>
>> Ref:
>>
>>
http://www.research.att.com/~njas/sequences/?q=id%3AA125887|id%3AA076654|id%3AA125886
>>
>> -----
>> I'm considering submitting (done by hand, so there may be errors):
>>
>> a(n+1) is the smallest number not yet in the sequence which contains
>> the last digit of a(n):
>>
>> 1,10,20,30,40,50,60,70,80,90,100,101,11,12,2,
>> 21,13,3,31,14,4,41,15,5,51,16,6,61,17,7,71,18,
>> 8,81,19,9,91,102,22,23,32,24,42,25,52,26,62,
>> 27,72,28,82,29,92,112,120,103,33,34,43,35,53,
>> 36,63,37,73,38,83,39,93,113,123,130,104,44,
>> 45,54,46,64,47,74,48,84,49,94,114,124,134,
>> 140,105,55,56,65,57,75,58,85,59,95,115,125,
>> 135,145,150,106,66,67,76,68,86,69,96,116,
>> 126,136,146,156,160,107,77,78,87,79,97,117,
>> 127,137,147,157,167,170,108,88,89,98,118,
>> 128,138,148,158,168,178,180,109,99,119,129,
>> 139,149,159,169,179,189,190,110,200,201,
>> 111,112,121,113,131,...
>>
>> I'm a bit reluctant to be adding yet another "base" sequence, however.
>>
>> Franklin T. Adams-Watters
>>> _______________________________________________
>>
>> Seqfan Mailing list - http://list.seqfan.eu/
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