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Search: id:A072404
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| A072404 |
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Denominator of the Reingold-Tarjan sequence, numerator=A072403. |
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+0
2
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| 1, 3, 9, 9, 27, 27, 3, 27, 81, 81, 27, 81, 81, 9, 81, 81, 243, 243, 27, 243, 243, 81, 243, 243, 81, 243, 243, 27, 243, 243, 81, 243, 729, 729, 243, 729, 729, 81, 729, 729, 243, 729, 729, 243, 729, 729, 9, 729, 729, 243, 729, 729, 243, 729, 729, 81
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OFFSET
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1,2
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COMMENT
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The the Reingold-Tarjan sequence is based on the following function defined on even positive integers and range of the rational numbers:
f(2*n) = if n is even then 2*f(n)/3 else (f(n+1)+f(n-1))/3 for n>1, f(2*1)=1.
f(2*n) = A072403(n)/a(n) for n>1, A072403(1)=1 and a(1)=1.
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REFERENCES
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J.-P. Allouche and J. Shallit, The ring of k-regular sequences (Example 33), Theoretical Computer Science, 98 (1992), 163-197.
E. M. Reingold and R. E. Tarjan, On a greedy heuristic for complete matching, SIAM J. Computing 10 (1981), 676-681.
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LINKS
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J.-P. Allouche and J. Shallit, The ring of k-regular sequences, Theoretical Computer Sci., 98 (1992), 163-197.
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CROSSREFS
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Sequence in context: A143225 A099720 A162349 this_sequence A125824 A038227 A080292
Adjacent sequences: A072401 A072402 A072403 this_sequence A072405 A072406 A072407
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KEYWORD
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nonn,frac
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 16 2002
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