A026141 a(n) = (s(n)-s(n-1))/2, where s = A026139.

1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 3, 2, 1, 3, 2, 1, 2, 1, 3, 3, 2, 1, 3, 2, 1

Offset

2,2

Links

Michael De Vlieger, Table of n, a(n) for n = 2..10002

F. M. Dekking, Permutations of N generated by left-right filling algorithms, arXiv:2001.08915 [math.CO], 2020.

Mathematica

Block[{a, r, s, nn = 105}, a[1] = 1; Do[If[! IntegerQ[a[#1]], Set[a[#1], i], Set[a[#2], i]] & @@ {i - #, i + #} &@ Floor[i/2], {i, 4 nn}]; s = TakeWhile[Array[a[#] &, 2 nn], IntegerQ]; Map[(#2 - #1)/2 & @@ # &, Partition[Union@ FoldList[Max, s], 2, 1]]] (* Michael De Vlieger, Aug 27 2021 *)

Crossrefs

Cf. A026136, A026139.

Sequence in context: A193865 A026171 A026176 * A089209 A153359 A240474

Adjacent sequences: A026138 A026139 A026140 * A026142 A026143 A026144

Keyword

nonn

Author

Clark Kimberling

Extensions

Edited by N. J. A. Sloane, Jan 31 2020

Status

approved