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A064622 revision #35

A064622

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

1, 2, 3, 6, 7, 19, 34, 67, 102, 115, 190, 2066, 24381, 24398, 24399, 36130540, 409493529, 3744514071, 17951662018, 71184216405

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

See A064621 for associated values of A005132.

No other terms < 4.61 * 10^11. - Jud McCranie, Dec 29 2019

LINKS

Table of n, a(n) for n=1..20.

Index entries for sequences related to Recamán's sequence

EXAMPLE

A005132(7)=20, 20/7 = 2.857..., larger than the ratio for any smaller value of n. So 7 is in the sequence.

MATHEMATICA

Block[{s = Nest[Append[#1, If[And[#3 > 0, FreeQ[#1, #3]], #3, #1[[-1]] + #2]] & @@ {#1, #2, #1[[-1]] - #2} & @@ {#, Length@ #} &, {0}, 10^5], t}, t = MapIndexed[#1/First@ #2 &, s]; -1 + Rest@ Map[FirstPosition[t, #][[1]] &, Union@ FoldList[Max, t]] ] (* Michael De Vlieger, Dec 29 2019 *)

CROSSREFS

Cf. A005132, A064621.

Sequence in context: A064970 A064292 A079663 * A119746 A328023 A265481

Adjacent sequences: A064619 A064620 A064621 * A064623 A064624 A064625

KEYWORD

nonn,more

AUTHOR

Jud McCranie, Sep 26 2001

EXTENSIONS

Two more terms from John W. Layman and N. J. A. Sloane, Oct 12 2001

Offset changed, a(19)-a(20) from Jud McCranie, Dec 28 2019

STATUS

proposed