A131094 Triangle where n-th row contains the smallest n positive integers (listed in order) with exactly n nonleading 0's in their binary representations.
2, 4, 9, 8, 17, 18, 16, 33, 34, 36, 32, 65, 66, 68, 72, 64, 129, 130, 132, 136, 144, 128, 257, 258, 260, 264, 272, 288, 256, 513, 514, 516, 520, 528, 544, 576, 512, 1025, 1026, 1028, 1032, 1040, 1056, 1088, 1152, 1024, 2049, 2050, 2052, 2056, 2064, 2080, 2112
Offset: 1
Examples
Binary representations of the terms in the first few rows: 10 100, 1001 1000, 10001, 10010 10000, 100001, 100010, 100100
Links
- Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened
Programs
-
Haskell
import Data.List (sort, nub) a131094 n k = a131094_tabl !! (n-1) !! (k-1) a131094_row n = a131094_tabl !! (n-1) a131094_tabl = [2] : f 2 [2] where f v ws = ys : f (v + 1) ys where ys = take v $ nub $ sort $ concatMap h ws h z = [2 * z, 4 * z + 1, 4 * z' + b] where (z', b) = divMod z 2 -- Reinhard Zumkeller, Feb 11 2015 -
Maple
A080791 := proc(n) local bdigs ; bdigs := convert(n,base,2) ; nops(bdigs)-add(i,i=bdigs) ; end: A131094 := proc(n) local a,i; a := [] ; i := 2^n ; while nops(a) < n do while A080791(i) <> n do i := i+1 ; od: a := [op(a),i] ; i := i+1 ; od: RETURN(a) ; end: seq(op(A131094(n)),n=1..10) ; # R. J. Mathar, Oct 17 2007
Extensions
More terms from R. J. Mathar, Oct 17 2007