%I A123179
%S A123179 1,121,1213231,1213231424341,121323142434152535451,
%T A123179 1213231424341525354516263646561,
%U A123179 1213231424341525354516263646561727374757671
%N A123179 a(1)=1 a(2)=121 and a(n)=a(n-1) n 2 n 3 n ... n (n-1) n 1, using concatenation.
%C A123179 An example of transition complete sequences, when n <= 9. One needs to 
               consider the base 10 complications when n >= 10. The number of digits 
               is given by d(n)=d(n-1)+2n-2 which is A002061.
%e A123179 a(4)=1213231424341=1213231 + 4 2 4 3 4 1.
%Y A123179 Cf. A108713, A002061.
%Y A123179 Sequence in context: A013749 A135825 A082215 this_sequence A136094 A053885 
               A068490
%Y A123179 Adjacent sequences: A123176 A123177 A123178 this_sequence A123180 A123181 
               A123182
%K A123179 nonn,base
%O A123179 1,2
%A A123179 Douglas Stones (dssto1(AT)student.monash.edu.au), Oct 03 2006