OFFSET
1,2
LINKS
Sean A. Irvine, Table of n, a(n) for n = 1..10000
F. M. Dekking, Permutations of N generated by left-right filling algorithms, arXiv:2001.08915 [math.CO], 2020.
MATHEMATICA
Block[{a, nn = 188}, a[1] = 1; Do[If[! IntegerQ[a[#1]], Set[a[#1], i], Set[a[#2], i]] & @@ {i - #, i + #} &@ Floor[i/2], {i, nn}]; a = TakeWhile[Array[a[#] &, nn], IntegerQ]; TakeWhile[Array[FirstPosition[a, #][[1]] &, nn], IntegerQ]] (* Michael De Vlieger, Apr 16 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Jan 31 2020
STATUS
approved