%I A100830
%S A100830 10,11,12,13,14,15,16,17,18,1,2,3,4,5,6,7,8,9,28,29,30,31,32,33,34,35,
%T A100830 36,19,20,21,22,23,24,25,26,27,46,47,48,49,50,51,52,53,54,37,38,39,40,
%U A100830 41,42,43,44,45,64,65,66,67,68,69,70,71,72,55,56,57,58,59,60,61,62,63
%N A100830 Smallest number with same digital root as n but distinct from n and all 
               earlier occurrences.
%C A100830 A010888(a(n)) = A010888(n) and a(n)<>n;
%C A100830 a(a(n))=n: self-inverse permutation of the natural numbers.
%H A100830 <a href="Sindx_Per.html#IntegerPermutation">Index entries for sequences 
               that are permutations of the natural numbers</a>
%F A100830 a(n) = n + 9*(-1)^floor((n-1)/9).
%Y A100830 Sequence in context: A162501 A123895 A147519 this_sequence A168100 A088475 
               A001637
%Y A100830 Adjacent sequences: A100827 A100828 A100829 this_sequence A100831 A100832 
               A100833
%K A100830 nonn,base
%O A100830 1,1
%A A100830 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 07 2005