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A026138
Numbers k such that s(j) < s(k) for all j < k, where s = A026136.
7
1, 2, 4, 5, 8, 10, 11, 13, 14, 17, 20, 22, 23, 26, 28, 29, 31, 32, 35, 37, 38, 40, 41, 44, 47, 49, 50, 53, 56, 58, 59, 62, 64, 65, 67, 68, 71, 74, 76, 77, 80, 82, 83, 85, 86, 89, 91, 92, 94, 95, 98, 101, 103, 104, 107, 109, 110, 112, 113
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
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
Cf. A026136, A026139 (records in A026136), A026169.
Sequence in context: A325442 A134191 A286803 * A026170 A026174 A120685
KEYWORD
nonn
EXTENSIONS
Edited by N. J. A. Sloane, Jan 31 2020
STATUS
approved