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Search: id:A130547
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| A130547 |
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Numerators of 6*(sum(1/binomial(2*k,k),k=1..n)-1/3), n>=1. |
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+0
3
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| 1, 2, 23, 167, 253, 5581, 13201, 48413, 823063, 15638407, 1117033, 89921239, 256917887, 60848977, 134111147453, 4157445588203, 1385815197541, 9700706385439, 358926136286437, 358926136292897, 474708760905697
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OFFSET
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1,2
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COMMENT
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Denominators are given by A130548.
The partial sums (in lowest terms) r(n):= 6*(sum(1/binomial(2*k,k),k=1..n)-1/3) tend, for n->infinity to 4*Pi*sqrt(3)/9, which is approximately 2.418399153.
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REFERENCES
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L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 89, Exercise (with a misprint).
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LINKS
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W. Lang, Rationals and limit.
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FORMULA
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a(n)=numer(r(n)), n>=1, with the rationals defined above.
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CROSSREFS
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Adjacent sequences: A130544 A130545 A130546 this_sequence A130548 A130549 A130550
Sequence in context: A143912 A041579 A053299 this_sequence A118756 A133955 A062600
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KEYWORD
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nonn,frac,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Jul 13 2007
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