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 A028580 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). 2
 1, 2, 10, 280, 235200, 173859840000, 98238542885683200000000, 32169371027674057560745102540800000000000000000, 3518552669874927170883258602839130084576857453953842493259776000000000000000000000000000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Essentially the same as A003047, which is the main entry. [From R. J. Mathar, Oct 23 2008] REFERENCES D.-Z. Du and F. K. Hwang, Combinatorial Group Testing and Its Applications, World Scientific, 2nd ed., 2000; p. 36. LINKS Table of n, a(n) for n=1..9. FORMULA a(n) = 2*(2n-1)*a(n-1)^2/(n+1). MATHEMATICA RecurrenceTable[{a[n] == 2*(2*n-1)*a[n-1]^2/(n+1), a[1]==1}, a, {n, 1, 10}] (* Vaclav Kotesovec, Mar 07 2019 *) CROSSREFS Cf. A003047, A000108. Sequence in context: A215286 A260231 A003047 * A171873 A098706 A143249 Adjacent sequences: A028577 A028578 A028579 * A028581 A028582 A028583 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, May 22 2000 EXTENSIONS More terms from James A. Sellers, May 22 2000 STATUS approved

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Last modified June 4 03:55 EDT 2023. Contains 363118 sequences. (Running on oeis4.)