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A333132 a(n) = n for n <= 3; thereafter a(n) = 2^(a(n-1)-1) + a(n-1).

%I A333132 #4 Mar 08 2020 21:46:57
%S A333132 1,2,3,7,71,1180591620717411303495
%N A333132 a(n) = n for n <= 3; thereafter a(n) = 2^(a(n-1)-1) + a(n-1).
%C A333132 The next term is too large to include.
%C A333132 a(n) = number of compositions of a(1) + number of compositions of a(2) + ... + number of compositions of a(n-1) for n > 2.
%F A333132 a(n) = n for n <= 2; thereafter a(n) = Sum_{k=1..n-1} 2^(a(k)-1).
%e A333132 a(5) = 71, 71 in base 2 (reverse order of digits) = 1110001.
%e A333132                                                     |||   |
%e A333132                                                     123   7
%t A333132 a[n_] := a[n] = If[n <= 3, n, 2^(a[n - 1] - 1) + a[n - 1]]; Table[a[n], {n, 1, 6}]
%Y A333132 Cf. A004249, A007516, A011782, A014221, A034797, A103527.
%K A333132 nonn
%O A333132 1,2
%A A333132 _Ilya Gutkovskiy_, Mar 08 2020