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%I #14 Dec 16 2015 00:07:12
%S 0,1,1,1,12,12,12,12,12,12,100,121,122,123,123,112,123,123,123,123,
%T 100,112,121,123,123,123,121,123,123,123,100,123,1023,1023,1123,1223,
%U 1234,1234,1222,1231,1200,1231,1234,1234,1234,1012,1223,1102,1203,1203,1200
%N a(n) = A123895(n^2).
%D D. E. Knuth, The Art of Computer Programming, vol. 4A, Combinatorial Algorithms, Section 7.2.1.5, p. 432, Problems 4 and 5.
%H Michael De Vlieger, <a href="/A123896/b123896.txt">Table of n, a(n) for n = 0..10000</a>
%t f[n_] := Block[{d = Prepend[IntegerDigits@ n, 0], a, b, w}, b = DeleteDuplicates@ d; a = Range[0, Length@ b]; w = FromDigits@ Flatten[Part[a, FirstPosition[b, #]] & /@ d]; w]; Table[f[n^2], {n, 0, 50}] (* _Michael De Vlieger_, Dec 09 2015, Version 10 *)
%K nonn,base
%O 0,5
%A _N. J. A. Sloane_, Nov 20 2006
%E More terms from _Franklin T. Adams-Watters_, Nov 20 2006