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.

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A338623 a(n) is the length of the longest block of consecutive terms appearing twice (possibly with overlap) among the first n terms of the Thue-Morse sequence (A010060).

Original entry on oeis.org

0, 0, 1, 1, 2, 2, 2, 2, 3, 4, 4, 4, 4, 4, 4, 4, 5, 6, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 10, 11, 12, 13, 14, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25
Offset: 1

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Author

Rémy Sigrist, Nov 04 2020

Keywords

Comments

This sequence is weakly increasing and unbounded (as A010060 is bounded).

Examples

			For n = 8:
- the first 8 terms of A010060 are 0, 1, 1, 0, 1, 0, 0, 1,
- the blocks (0, 1) and (1, 0) are repeated, and there are no length-3 repeated block,
- so a(8) = 2.
		

Crossrefs

Cf. A010060, A304588, A338624 (Kolakoski variant).

Programs

  • PARI
    See Links section.

Formula

a(n) <= a(n+1) <= a(n) + 1.
a(A304588(n)) = n (and this is the first occurrence of n in the sequence).

A338626 a(n) is the least k such that the first k terms of the Kolakoski sequence (A000002) contain a length-n repeated block.

Original entry on oeis.org

3, 6, 9, 10, 13, 15, 16, 28, 32, 33, 40, 41, 42, 43, 69, 70, 71, 72, 94, 95, 96, 97, 98, 99, 106, 107, 108, 109, 214, 215, 216, 217, 218, 219, 220, 221, 222, 297, 298, 299, 300, 301, 339, 340, 487, 719, 720, 721, 722, 723, 724, 725, 726, 727, 728, 729, 730
Offset: 1

Views

Author

Rémy Sigrist, Nov 04 2020

Keywords

Comments

The sequence contains large runs of consecutive integers.

Examples

			For n = 2:
- the first 5 terms of Kolakoski sequence are: 1, 2, 2, 1, 1,
- they have no length-2 repeated block,
- the first 6 terms of Kolakoski sequence are: 1, 2, 2, 1, 1, 2,
- they have a length-2 repeated block: 1, 2,
- so a(2) = 6.
		

Crossrefs

Cf. A000002, A304588 (Thue-Morse variant), A338624.

Programs

  • PARI
    See Links section.
    
  • Perl
    See Links section.

Formula

A338624(a(n)) = n.
Showing 1-2 of 2 results.