%I #11 Sep 02 2019 08:47:04
%S 2,3,4,7,10,15,21,31,44,63,89,127,180,255,361,511,723,1023,1447,2047,
%T 2895,4095,5791,8191,11584,16383,23169,32767,46339,65535,92680,131071,
%U 185362,262143,370726,524287,741454,1048575,1482909,2097151,2965819,4194303,5931640,8388607
%N a(n) = A055086(2^n).
%C a(2n-2)=2^n-1 and a(n)=2a(n-2)+1 generally.
%t Table[ Length[ Union[ Table[ Floor[2^w/j], {j, 1, 2^w}]]], {w, 1, 25}]
%o (PARI) a(n) = ceil(2*sqrt(2^n+1)) - 2; \\ _Michel Marcus_, Sep 02 2019
%Y Cf. A055086, A078160, A078161 & A078162.
%K nonn
%O 1,1
%A _Labos Elemer_, Nov 27 2002
%E Extended by _Robert G. Wilson v_, Dec 02 2002
%E More terms from _Michel Marcus_, Sep 02 2019
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