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A003047 a(n) = Catalan(n) * Product_{k = 0..n-1} a(k).
(Formerly M1993)
2

%I M1993 #34 Oct 20 2023 22:34:08

%S 1,1,2,10,280,235200,173859840000,98238542885683200000000,

%T 32169371027674057560745102540800000000000000000,

%U 3518552669874927170883258602839130084576857453953842493259776000000000000000000000000000000000

%N a(n) = Catalan(n) * Product_{k = 0..n-1} a(k).

%D D.-Z. Du and F. K. Hwang, Combinatorial Group Testing and Its Applications, World Scientific, 2nd ed., 2000; p. 36.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H J. W. Moon, R. K. Guy, and N. J. A. Sloane, <a href="/A003046/a003046.pdf">Correspondence, 1973</a>.

%H J. W. Moon and M. Sobel, <a href="https://doi.org/10.1016/0095-8956(77)90030-2">Enumerating a class of nested group testing procedures</a>, J. Combin. Theory, B23 (1977), 184-188.

%F a(n) = ((4*n-6)*a(n-1)^2)/n, for n > 1. - _Christian Krause_, Oct 13 2023

%Y See A028580 for another version. Cf. A000108, A003046.

%K easy,nonn

%O 1,3

%A _N. J. A. Sloane_

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Last modified March 29 06:44 EDT 2024. Contains 371265 sequences. (Running on oeis4.)