A330788 Values of k at which the ratio k/A005132(k) sets a new record.

1, 4, 31, 62, 64, 111, 129, 131, 30764, 30766, 30768, 56127, 56167, 56199, 56513, 56515, 56827, 99734, 58055311, 904012796, 904032692, 1610175617, 1610178287, 1610186343, 2789149734, 13808214835, 325374625053, 325374625245

Offset

1,2

Comments

No other terms < 4.61 * 10^11.

Links

Table of n, a(n) for n=1..28.

Index entries for sequences related to Recamán's sequence

Example

A005132(131) = 4, 131/4 = 32.75, a higher ratio than any smaller term in A005132, so 131 is in the sequence.

Mathematica

Block[{s = MapIndexed[First[#2]/#1 &, Rest@ Nest[Append[#, If[And[#3 > 0, FreeQ[#1, #3]], #3, #1[[-1]] + #2]] & @@ {#, Length@ #, #[[-1]] - Length@ #} &, {0}, 10^5]], t}, t = Union@ FoldList[Max, Rest@ s]; MapAt[# - 1 &, #, 1] &@ Map[FirstPosition[s, #][[1]] &, t]] (* Michael De Vlieger, Jan 01 2020 *)

Crossrefs

Cf. A005132, A064622, A330789.

Sequence in context: A216302 A070522 A087689 * A374720 A210377 A211629

Adjacent sequences: A330785 A330786 A330787 * A330789 A330790 A330791

Keyword

nonn

Author

Jud McCranie, Dec 31 2019

Status

approved