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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A187186 Parse the infinite string 0123456701234567012345670... into distinct phrases 0, 1, 2, 3, 4, 5, 6, 7, 01, 23, 45, 67, 012, 34, ...; a(n) = length of n-th phrase.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 5, 4, 4, 5, 4, 4, 5, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 10, 10, 10, 10, 11, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 12, 12, 13, 12, 12, 13, 12, 12, 13, 12, 12, 13, 13, 13, 13, 13, 14, 14, 14, 14, 15, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15
Offset: 1

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Author

N. J. A. Sloane, Mar 06 2011

Keywords

Comments

See A187180 for details.

Crossrefs

See A187180-A187188 for alphabets of size 2 through 10.

Formula

After the initial block of eight 1's, the sequence is quasi-periodic with period 64, increasing by 8 after each block.

A187201 Parse Gijswijt's sequence A090822 into distinct phrases 1, 12, 11, 2, 22, 3, 112, 1122, 23, ...; a(n) = length of n-th phrase.

Original entry on oeis.org

1, 2, 2, 1, 2, 1, 3, 4, 2, 2, 3, 3, 3, 4, 3, 2, 3, 4, 3, 5, 4, 6, 3, 4, 4, 2, 7, 3, 4, 3, 5, 5, 5, 8, 3, 4, 5, 5, 5, 4, 2, 5, 5, 6, 4, 7, 4, 6, 5, 5, 6, 6, 6, 5, 4, 2, 8, 3, 7, 6, 6, 8, 6, 3, 9, 10, 10, 9, 7, 7, 9, 10, 10, 9, 7, 7, 6, 5, 4, 8, 10, 8, 8, 4, 7, 6, 3, 8, 5, 6, 9, 4, 7, 8, 10, 11, 11, 8, 9, 4
Offset: 1

Views

Author

N. J. A. Sloane, Mar 06 2011

Keywords

Crossrefs

A288533 Parse A004736 into distinct phrases [1], [2], [1,3], [2,1], [4], [3], [2,1,5], [4,3], [2,1,6], ...; a(n) is the length of the n-th phrase.

Original entry on oeis.org

1, 1, 2, 2, 1, 1, 3, 2, 3, 1, 3, 2, 1, 2, 2, 2, 1, 2, 4, 1, 1, 2, 3, 3, 2, 3, 5, 1, 3, 3, 3, 1, 1, 2, 2, 4, 3, 2, 3, 4, 4, 1, 3, 4, 4, 2, 1, 2, 2, 5, 5, 1, 2, 4, 3, 5, 1, 1, 2, 3, 4, 5, 2, 2, 3, 5, 5, 3, 1, 3, 3, 3, 4, 5, 1, 2, 2, 4, 5, 6, 1, 2, 4, 4, 6, 4, 1, 2, 3, 4, 4, 6, 2, 1, 2, 3, 3, 5, 5, 4, 1, 2, 3, 5, 6, 6, 1, 1, 2, 3, 4, 5, 7, 3, 2, 3, 4, 4, 7, 6, 1, 3, 3, 4, 5, 6, 5, 1, 2, 2
Offset: 1

Views

Author

Lewis Chen, Jun 11 2017

Keywords

Comments

The phrases are formed by the Ziv-Lempel encoding described in A106182. - Neal Gersh Tolunsky, Nov 30 2023

Examples

			Consider the infinite sequence [1,2,1,3,2,1,4,3,2,1,5,4,3,2,1,...], i.e., A004736. We can first take [1] since we've never used it before. Then [2]. For the third term, we've already used [1], so we must instead take [1,3].
		

Crossrefs

Programs

  • Python
    # you should use program from internal format
    a = set()
    i = 2
    s = "1"
    seq = ""
    while i < 100:
        j = i
        while j > 0:
            if s not in a:
                seq = seq + "," + str(len(s)-len(s.replace(",",""))+1)
                a.add(s)
                s = str(j)
            else:
                s = s + "," + str(j)
            j -= 1
        i += 1
    print(seq[1:])
Previous Showing 11-13 of 13 results.