A258047 Sequence (d(n)) generated by Rule 3 (in Comments) with a(1) = 1 and d(1) = 0.
0, 1, 2, -1, 3, 6, -7, 5, -3, 7, -6, 8, -5, -2, 9, 18, -23, 13, -11, 15, -13, 17, -15, 19, -18, 20, -19, 21, -20, 22, -21, 23, -22, 24, -17, -4, 27, -29, 25, -9, -12, 29, -30, 28, -24, 32, -31, 33, -27, 4, -8, 35, -33, 37, -25, 49, -53, 45, -43, 47, -42, 52
Offset: 1
Examples
a(1) = 1, d(1) = 0; a(2) = 2, d(2) = 1; a(3) = 4, d(3) = 2; a(4) = 3, d(4) = -1.
Links
- Clark Kimberling, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
{a, f} = {{1}, {0}}; 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 *)
Comments