OFFSET
1,2
COMMENTS
Also a(n) = (1/2)*s(n+1), where s = A026169.
That these definitions produce the same sequence can be established using the methods in the Dekking paper.
Indices of records in A026136. - Michael De Vlieger, Aug 27 2021
LINKS
Michael De Vlieger, 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, r, s, nn = 113}, a[1] = 1; Do[If[! IntegerQ[a[#1]], Set[a[#1], i], Set[a[#2], i]] & @@ {i - #, i + #} &@ Floor[i/2], {i, 2 nn}]; s = TakeWhile[Array[a[#] &, nn], IntegerQ]; Map[FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]] (* Michael De Vlieger, Aug 27 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Jan 31 2020
STATUS
approved