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.

A342799 Numbers m such that there are more 1s than 2s in {K(1), .., K(m)}, where K = A000002 (Kolakoski sequence).

Original entry on oeis.org

1, 5, 7, 17, 23, 25, 29, 31, 32, 33, 34, 35, 37, 41, 43, 49, 51, 52, 53, 55, 59, 61, 71, 73, 79, 125, 131, 133, 134, 135, 137, 141, 143, 149, 161, 179, 185, 187, 191, 193, 194, 195, 196, 197, 199, 201, 202, 203, 205, 209, 211, 221, 223, 227, 229, 230, 231
Offset: 1

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Author

Clark Kimberling, May 10 2021

Keywords

Comments

The three sequences A022292 (without the initial 0), A074261, and A342799 partition the positive integers.

Examples

			The Kolakoski sequence is (1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, ...), so that a(1) = 1, a(2) = 5.
		

Crossrefs

Programs

  • Mathematica
    k = Prepend[Nest[Flatten[Partition[#, 2] /. {{2, 2} -> {2, 2, 1, 1}, {2, 1} -> {2, 2, 1}, {1, 2} -> {2, 1, 1}, {1, 1} -> {2, 1}}] &, {2, 2}, 14], 1]; (* A000002 *)
    Select[Range[400], Count[Take[k, #], 1] < #/2 &]   (* A074261 *)
    Select[Range[400], Count[Take[k, #], 1] == #/2 &]  (* A022292 *)
    Select[Range[400], Count[Take[k, #], 1] > #/2 &]   (* A342799 *)