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Search: id:A028580
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| A028580 |
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C_{n+1}*C_n*C_{n-1}^2*C_{n-2}^4*...*C_2^{2^(n-2)}, where C_k are the Catalan numbers (A000108). |
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+0
2
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| 1, 2, 10, 280, 235200, 173859840000, 98238542885683200000000, 32169371027674057560745102540800000000000000000, 35185526698749271708832586028391300845768574539538424932597760000000000000000000\ 00000000000000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Essentially the same as A003047. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 23 2008]
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REFERENCES
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D.-Z. Du and F. K. Hwang, Combinatorial Group Testing and Its Applications, World Scientific, 2nd ed., 2000; p. 36.
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FORMULA
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a(n) = 2*(2n-1)*a(n-1)^2/(n+1).
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CROSSREFS
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Sequence in context: A074056 A144288 A003047 this_sequence A098706 A143249 A161181
Adjacent sequences: A028577 A028578 A028579 this_sequence A028581 A028582 A028583
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), May 22 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 22 2000
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