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%I #8 Nov 19 2013 20:09:56
%S 2,7,24,80,238,723,2183,5653,19674,59042,177145,531429,1594313,
%T 4782955,14348892,43046708,129140146,387420471,1162261451,3486784397,
%U 10460353182,31381059590,94143178804,282429536457,847288609421
%N Numbers missing from A109681.
%C 3^(n-1) < a(n) < 3^n. - _Reinhard Zumkeller_, Nov 19 2013
%o (Haskell)
%o -- import Data.List (delete)
%o a109682 n = a109682_list !! (n-1)
%o a109682_list = compl a109681_list [0..] where
%o compl us'@(u:us) vs'@(v:vs)
%o | u == v = compl us vs
%o | u > 3 * v = v : compl us (delete u vs)
%o | otherwise = compl us (delete u vs')
%o -- _Reinhard Zumkeller_, Nov 19 2013
%Y Cf. A109681, A109683, also A109684 (ternary equivalents).
%K nonn
%O 1,1
%A _Philippe Deléham_, Aug 08 2005