A064579 - OEIS

A064579

Inverse permutation to A054082.

2, 1, 4, 3, 6, 8, 5, 10, 7, 12, 14, 9, 16, 18, 11, 20, 13, 22, 24, 15, 26, 17, 28, 30, 19, 32, 34, 21, 36, 23, 38, 40, 25, 42, 44, 27, 46, 29, 48, 50, 31, 52, 33, 54, 56, 35, 58, 60, 37, 62, 39, 64, 66, 41, 68, 43, 70, 72, 45, 74, 76, 47, 78, 49, 80, 82, 51, 84, 86, 53, 88, 55

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..72.

Index entries for sequences that are permutations of the natural numbers

MAPLE

A054082 := proc(nmax) local a, k, n, p ; a := [2, 1] ; while nops(a) < nmax do n := nops(a)+1 : k := floor((n+1)/2) ; p := 1; while p in a do p := p+1 ; od ; if n mod 2 = 1 then a := [op(a), p+k-1] ; else a := [op(a), p] ; fi ; od ; RETURN(a) ; end: A064579 := proc(a054082) local a, n, ainv ; n := 1; a := [] ; while member(n, a054082, 'ainv') do a := [op(a), ainv] ; n := n+1; od; RETURN(a) ; end: a054082 := A054082(200) : a064579 := A064579(a054082) : print(op(a064579)) ; # R. J. Mathar, Jun 27 2007

MATHEMATICA

a[n_] := If[OddQ[n], Floor[((n+1)/2 - 1) GoldenRatio] + (n+1)/2 + 1, Floor[(n/2 - 1) GoldenRatio] + 2]; a[2] = 1;

Sort[Array[{a[#], #}&, 100]][[All, 2]] (* Jean-François Alcover, Apr 01 2020 *)

CROSSREFS

Cf. A054082.

Sequence in context: A352111 A352112 A114862 * A277376 A105361 A370728

Adjacent sequences: A064576 A064577 A064578 * A064580 A064581 A064582

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Oct 16 2001

EXTENSIONS

Corrected and extended by R. J. Mathar, Jun 27 2007

STATUS

approved