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%I #15 Dec 18 2022 07:03:46
%S 1,1,2,1,1,2,1,1,2,1,2,1,2,1,3,1,1,2,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,3,
%T 1,2,1,3,1,2,1,1,1,2,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,3,1,2,1,3,1,2,1,1,
%U 1,2,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,3,1,2,1,3,1,2,1,1,2,1,2,1,3,1,2,1,3,1,2
%N A nonsense sequence.
%F Involves substitutions 1-> {1, 2}, 2->{1, 3}, 3->1.
%t Hofstadter[n_Integer? Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n - 1]] + Hofstadter[n - Hofstadter[n - 2]];
%t Hofstadter[0] = Hofstadter[1] = 1;
%t s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {1};
%t t[a_] := Join[a, Flatten[s /@ a]];
%t p[0] = {1}; p[1] = t[{1}];
%t p[n_] := t[p[n - 1]];
%t Flatten[Table[p[If[n > 0, Hofstadter[n], n]], {n, 0, 7}]]
%Y Cf. A073058, A103684.
%K nonn,uned,less
%O 0,3
%A _Roger L. Bagula_, Mar 30 2005
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