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Revision History for A257983

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Sequence (a(n)) generated by Rule 3 (in Comments) with a(1) = 1 and d(1) = 2.
(history; published version)
#7 by N. J. A. Sloane at Tue Jun 16 13:54:12 EDT 2015
STATUS

proposed

approved

#6 by Clark Kimberling at Mon Jun 15 19:07:52 EDT 2015
STATUS

editing

proposed

#5 by Clark Kimberling at Mon Jun 15 19:00:45 EDT 2015
CROSSREFS
STATUS

approved

editing

#4 by N. J. A. Sloane at Fri Jun 05 03:42:41 EDT 2015
STATUS

proposed

approved

#3 by Clark Kimberling at Tue May 19 10:49:04 EDT 2015
STATUS

editing

proposed

#2 by Clark Kimberling at Tue May 19 10:46:28 EDT 2015
NAME

allocated for Clark KimberlingSequence (a(n)) generated by Rule 3 (in Comments) with a(1) = 1 and d(1) = 2.

DATA

1, 2, 5, 3, 7, 4, 9, 8, 16, 6, 12, 24, 10, 20, 11, 22, 14, 28, 13, 26, 15, 30, 17, 34, 18, 36, 19, 38, 31, 25, 21, 42, 23, 46, 41, 29, 58, 27, 54, 32, 64, 35, 70, 33, 66, 39, 78, 37, 74, 40, 80, 44, 88, 43, 86, 47, 94, 45, 90, 48, 96, 49, 98, 50, 100, 56

OFFSET

1,2

COMMENTS

Rule 3 follows. For k >= 1, let A(k) = {a(1), …, a(k)} and D(k) = {d(1), …, d(k)}. Begin with k = 1 and nonnegative integers a(1) and d(1).

Step 1: If there is an integer h such that 1 - a(k) < h < 0 and h is not in D(k) and a(k) + h is not in A(k), let d(k+1) be the least such h, let a(k+1) = a(k) + h, replace k by k + 1, and repeat Step 1; otherwise do Step 2.

Step 2: Let h be the least positive integer not in D(k) such that a(k) - h is not in A(k). Let a(k+1) = a(k) + h and d(k+1) = h. Replace k by k+1 and do Step 1.

See A257905 for a guide to related sequences and conjectures.

LINKS

Clark Kimberling, <a href="/A257983/b257983.txt">Table of n, a(n) for n = 1..1000</a>

EXAMPLE

a(1) = 1, d(1) = 2;

a(2) = 2, d(2) = 1;

a(3) = 5, d(3) = 3;

a(4) = 3, d(4) = -2.

MATHEMATICA

{a, f} = {{1}, {2}}; Do[tmp = {#, # - Last[a]} &[Min[Complement[#, Intersection[a, #]]&[Last[a] + Complement[#, Intersection[f, #]] &[Range[2 - Last[a], -1]]]]];

If[! IntegerQ[tmp[[1]]], tmp = {Last[a] + #, #} &[NestWhile[# + 1 &, 1, ! (! MemberQ[f, #] && ! MemberQ[a, Last[a] - #]) &]]]; AppendTo[a, tmp[[1]]]; AppendTo[f, tmp[[2]]], {120}]; {a, f} (* Peter J. C. Moses, May 14 2015 *)

CROSSREFS
KEYWORD

allocated

nonn,easy

AUTHOR

Clark Kimberling, May 19 2015

STATUS

approved

editing

#1 by Clark Kimberling at Fri May 15 19:09:01 EDT 2015
NAME

allocated for Clark Kimberling

KEYWORD

allocated

STATUS

approved