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%I #15 Jan 02 2023 12:30:50
%S 0,1,2,3,4,5,6,10,7,11,8,12,9,20,13,14,15,16,17,18,30,21,22,23,24,25,
%T 26,27,29,200,31,32,33,34,35,36,38,100,40,41,42,43,44,45,47,101,50,51,
%U 52,53,54,56,102,60,61,62,63,65,103,80,70,71,72,74,104
%N The sum of two neighboring digits is a palindrome; a(n) is the smallest possible nonnegative integer not occurring earlier.
%C The sum of two digits is a palindrome iff it is less than 10 or equal to 11. Therefore, numbers with substrings 19, 28, 37, 39, 46, ... (this is not A065207) can never occur, and this is not a permutation of the nonnegative integers.
%H E. Angelini, <a href="http://list.seqfan.eu/oldermail/seqfan/2014-January/012397.html">Palindromes -- with digits</a>, SeqFan List, Jan 27 2014.
%o (PARI) a=u=0;(isp(s)=s<10||s==11);for(n=1,100,print1(a",");u+=1<<a;for(k=1,9e9,bittest(u,k)&&next; for(j=1,#d=digits(k), isp(if(j>1,d[j-1],a%10)+d[j])&&next;k=(k\10^(#d-j)+1)*10^(#d-j)-1;next(2));a=k;break))
%Y Cf. A228730.
%K nonn,base
%O 0,3
%A _Eric Angelini_ and _M. F. Hasler_, Jan 29 2014
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