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A109734 In A109732, the number 2n+1 appears in position a(n). 5
1, 2, 5, 3, 30, 6, 28, 4, 38, 26, 11, 7, 36, 29, 14, 8, 201, 39, 34, 27, 180, 12, 175, 9, 199, 37, 46, 31, 25, 15, 178, 10, 242, 202, 49, 40, 197, 35, 54, 32, 192, 158, 23, 13, 208, 176, 57, 16, 240, 200, 61, 41, 83, 47, 195, 33, 121, 42, 67, 17, 190, 179, 70, 18, 689, 243 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

N. J. A. Sloane and Alois P. Heinz, Table of n, a(n) for n = 0..20000 (first 1024 terms from N. J. A. Sloane)

EXAMPLE

9 appears in position 30 in A109732, so a(4) = 30.

MAPLE

with(LinearAlgebra);

hit:=Array(1..200000); a:=[1, 3, 7];

hit[1]:=1; hit[3]:=2; hit[7]:=3; S:={15}; L:=7;

for n from 4 to 20000 do

if (L mod 3 = 0) and hit[L/3]=0 then

L:=L/3; a:=[op(a), L]; hit[L]:=n; S:= S minus {L};

   if hit[2*L+1]=0 then S:=S union {2*L+1}; fi;

else L:=min(S); a:=[op(a), L]; hit[L]:=n; S:=S minus {L};

   if hit[2*L+1]=0 then S:=S union {2*L+1}; fi;

fi;

od:

#a;

w:=[];

for i from 0 to 50000 do

if hit[2*i+1]=0 then break; fi;

w:=[op(w), hit[2*i+1]]; od:

w; # N. J. A. Sloane, Aug 25 2015

MATHEMATICA

(* using the M generated in A109732 *) ms=Sort[M]; k=1; While[ms[[k]]==2k-1, k++ ]; k=k-1; Take[Ordering[M], k] (* T. D. Noe, Aug 10 2005 *)

CROSSREFS

Cf. A109732. For records see A109739 and A109740.

Sequence in context: A051497 A246556 A264137 * A239309 A077073 A307126

Adjacent sequences:  A109731 A109732 A109733 * A109735 A109736 A109737

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 10 2005

EXTENSIONS

More terms from T. D. Noe and Ray Chandler, Aug 10 2005

STATUS

approved

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Last modified June 24 17:50 EDT 2019. Contains 324330 sequences. (Running on oeis4.)