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A057167 Term in Recamán's sequence A005132 where n appears for first time, or 0 if n never appears. 19

%I

%S 1,4,2,131,129,3,5,16,14,12,10,8,6,31,29,27,25,23,99734,7,9,11,13,15,

%T 17,64,62,60,58,56,54,52,50,48,46,44,42,40,38,111,22,20,18,28,30,32,

%U 222,220,218,216,214,212,210,208,206,204,202,200,198,196

%N Term in Recamán's sequence A005132 where n appears for first time, or 0 if n never appears.

%H T. D. Noe, <a href="/A057167/b057167.txt">Table of n, a(n) for n=1..1642</a> (taking a(1355) from A064227)

%H Nick Hobson, <a href="/A057167/a057167.py.txt">Python program for this sequence</a>

%H C. L. Mallows, <a href="/A005132/a005132.jpg">Plot (jpeg) of first 10000 terms of A005132</a>

%H C. L. Mallows, <a href="/A005132/a005132.ps">Plot (postscript) of first 10000 terms of A005132</a>

%H N. J. A. Sloane, <a href="http://neilsloane.com/doc/sg.txt">My favorite integer sequences</a>, in Sequences and their Applications (Proceedings of SETA '98).

%H N. J. A. Sloane, <a href="/A005132/a005132.txt">FORTRAN program for A005132, A057167, A064227, A064228</a>

%H <a href="/index/Rea#Recaman">Index entries for sequences related to Recamán's sequence</a>

%p w := array(1..10000); for j from 1 to 100 do l := 0; for k from 1 to nops(a) do if a[k] = j then l := k; exit; fi; od: w[j] := l; od: s := [seq(w[j],j=1..100)]; # where a is an array formed from sequence A005132

%t A005132 = {0}; Do[If[(r = Last[A005132] - n) <= 0 || MemberQ[ A005132, r], r = r + 2n]; AppendTo[ A005132, r], {n, 1, 10^5}]; a[n_] := If[p = Position[ A005132, n]; p == {}, 0, p[[1, 1]] - 1]; Table[a[n], {n, 1, 60}] (* _Jean-François Alcover_, Jul 18 2012 *)

%Y Cf. A005132, A057165, A057166.

%Y Cf. A187943, A187922.

%K nonn,easy,nice,look

%O 1,2

%A _N. J. A. Sloane_, Sep 14 2000

%E I conjecture a(n) is never 0 - but see A064227, A064228.

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Last modified November 21 09:11 EST 2018. Contains 317431 sequences. (Running on oeis4.)