cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A187570 Rank transform of the sequence ceiling(n/3); complement of A187571.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, 22, 24, 25, 26, 28, 29, 30, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 52, 54, 55, 56, 58, 59, 60, 62, 63, 64, 66, 67, 68, 70, 71, 72, 73, 74, 75, 77, 78, 79, 81, 82, 83, 85, 86, 87, 88, 89, 90, 92, 93, 94, 96, 97, 98, 100, 101, 102, 103, 104, 105, 107, 108, 109, 111, 112, 113, 115, 116
Offset: 1

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Author

Clark Kimberling, Mar 11 2011

Keywords

Comments

Appears to be a duplicate of A045749. - R. J. Mathar, Mar 15 2011
The Mathematica programs shown at A187570 and A045749 confirm equality of the first 500 terms. - Clark Kimberling, Apr 02 2011
The sequence of which A187570 is the rank transform is (1,1,1,2,2,2,3,3,3,4,4,4,...), which is (A002264 without the initial three zeros). For a discussion on rank transforms, see A187224.

Crossrefs

Programs

  • Mathematica
    seqA = Table[Ceiling[n/3], {n, 1, 220}]  (*A002264*)
    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]] (*A187570*)
    Complement[Range[Length[seqA]], limseqU]  (*A187571*)
    (*by Peter J. C. Moses, Mar 11 2011*)