A109682 Numbers missing from A109681.

2, 7, 24, 80, 238, 723, 2183, 5653, 19674, 59042, 177145, 531429, 1594313, 4782955, 14348892, 43046708, 129140146, 387420471, 1162261451, 3486784397, 10460353182, 31381059590, 94143178804, 282429536457, 847288609421

Offset

1,1

Comments

3^(n-1) < a(n) < 3^n. - Reinhard Zumkeller, Nov 19 2013

Links

Table of n, a(n) for n=1..25.

Prog

(Haskell)
-- import Data.List (delete)
a109682 n = a109682_list !! (n-1)
a109682_list = compl a109681_list [0..] where
   compl us'@(u:us) vs'@(v:vs)
       | u == v    = compl us vs
       | u > 3 * v = v : compl us (delete u vs)
       | otherwise = compl us (delete u vs')
-- Reinhard Zumkeller, Nov 19 2013

Crossrefs

Cf. A109681, A109683, also A109684 (ternary equivalents).

Sequence in context: A024024 A027122 A132788 * A215694 A027124 A038765

Adjacent sequences: A109679 A109680 A109681 * A109683 A109684 A109685

Keyword

nonn

Author

Philippe Deléham, Aug 08 2005

Status

approved