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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A380107 a(1) = 0; for n >= 1, if there exists an m < n such that a(m) = a(n), take the largest such m and let a(n+1) be the number of distinct runs in the subsequence a(m)..a(n-1). Otherwise, a(n+1) = 0.

Original entry on oeis.org

0, 0, 1, 0, 2, 0, 2, 2, 1, 4, 0, 4, 2, 4, 2, 2, 1, 5, 0, 6, 0, 2, 5, 4, 7, 0, 5, 4, 4, 1, 8, 0, 5, 5, 1, 4, 5, 3, 0, 6, 11, 0, 3, 4, 6, 5, 6, 2, 12, 0, 7, 13, 0, 3, 9, 0, 3, 3, 1, 13, 6, 10, 0, 6, 3, 6, 2, 11, 14, 0, 6, 5, 14, 4, 15, 0, 6, 6, 1, 13, 13, 1, 2, 11, 11
Offset: 1

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Author

Neal Gersh Tolunsky, Jan 12 2025

Keywords

Comments

This is a variant of Van Eck's sequence A181391 in which we count distinct runs of consecutive equal values rather than individual terms.
The longest run in the sequence has length 2.

Examples

			a(10)=4: We find that the most recent occurrence of a(n) = a(9) = 1 is a(3) = 1. In between a(3) and a(8), we find 4 distinct runs: [1]; [0]; [2]; [2,2]. So a(10)=4.
		

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