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).

1, 2, 10, 280, 235200, 173859840000, 98238542885683200000000, 32169371027674057560745102540800000000000000000, 3518552669874927170883258602839130084576857453953842493259776000000000000000000000000000000000

Offset: 1

Author

N. J. A. Sloane, May 22 2000

Keywords

• nonn
• easy

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.

Crossrefs

Cf. A003047, A000108.

Programs

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 *)

Formula

a(n) = 2*(2n-1)*a(n-1)^2/(n+1).

Extensions

More terms from James Sellers, May 22 2000