A187681 Rank transform of the sequence floor(n/3); complement of A187682.

1, 2, 3, 4, 5, 7, 8, 9, 11, 12, 13, 15, 16, 17, 19, 20, 21, 23, 24, 25, 26, 27, 28, 30, 31, 32, 34, 35, 36, 38, 39, 40, 41, 42, 43, 45, 46, 47, 49, 50, 51, 53, 54, 55, 56, 57, 58, 60, 61, 62, 64, 65, 66, 68, 69, 70, 71, 72, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 86, 87, 88, 90, 91, 92, 94, 95, 96, 98, 99, 100, 102, 103, 104, 106, 107, 108, 110, 111, 112, 113, 114, 115, 117, 118, 119, 121, 122

Offset: 1

Author

Clark Kimberling, Mar 12 2011

Keywords

• nonn

Comments

See A187224.

Crossrefs

Cf. A187224, A187682, A187683, A187685, A187687.

Programs

Mathematica

seqA = Table[Floor[n/3], {n, 1, 220}]
seqB = Table[n, {n, 1, 220}];(*A000027*)
jointRank[{seqA_,
   seqB_}] := {Flatten@Position[#1, {_, 1}],
    Flatten@Position[#1, {_, 2}]} &[
  Sort@Flatten[{{#1, 1} & /@ seqA, {#1, 2} & /@ seqB}, 1]];
limseqU =
 FixedPoint[jointRank[{seqA, #1[[1]]}] &,
   jointRank[{seqA, seqB}]][[1]] (*A187681*)
Complement[Range[Length[seqA]], limseqU]  (*A187682*)
(*by Peter J. C. Moses, Mar 12 2011*)