%I A123121
%S A123121 1,3,7,15,31,63,127,255,511,1024,2050,4102,8206,16414,32830,65662,
%T A123121 131326,262654,525310,1050622,2101246,4202494,8404990,16809982,33619966,
%U A123121 67239934,134479870,268959742,537919486,1075838974,2151677950
%N A123121 Length of the n-th Zimin word (A082215(n)).
%D A123121 L. J. Cummings and M. Mays, A one-sided Zimin construction, Electron. 
               J. Combin. 8 (2001), #R27
%D A123121 A. I. Zimin, Blocking sets of terms, Math. USSR Sbornik, 47 (1984), No. 
               2, 353-364.
%F A123121 L(n) = 2*L(n-1) + ceil(log_10(n+1))
%e A123121 The Zimin words are defined by Z_1 = 1, Z_n = Z_{n-1}nZ_{n-1}.
%e A123121 So the Zimin words are 1, 121, 1213121, 121312141213121 ...
%Y A123121 Cf. A082215.
%Y A123121 Sequence in context: A060152 A126646 A000225 this_sequence A117060 A057613 
               A146686
%Y A123121 Adjacent sequences: A123118 A123119 A123120 this_sequence A123122 A123123 
               A123124
%K A123121 nonn
%O A123121 1,2
%A A123121 Dmitry Kamenetsky (Dmitry.Kamenetsky(AT)rsise.anu.edu.au), Sep 29 2006