A372989 a(n) = floor((2*n)!/(n!^2*a(n-1))), with a(0)=1.

1, 2, 3, 6, 11, 22, 42, 81, 158, 307, 601, 1173, 2305, 4512, 8891, 17446, 34453, 67733, 133983, 263804, 522533, 1030093, 2042630, 4030798, 8000302, 15800729, 31385800, 62032493, 123301357, 243851870, 484985337, 959675103, 1909629764, 3780538285, 7526187894

Offset

0,2

Links

Table of n, a(n) for n=0..34.

Mathematica

a[0] = 1; a[n_] := a[n] = Floor[(2 n)!/( (n!)^2*a[n - 1])];
Table[a[n], {n, 0, 40}]

Crossrefs

Cf. A372990.

Sequence in context: A036589 A251656 A123341 * A238351 A043328 A141072

Adjacent sequences: A372986 A372987 A372988 * A372990 A372991 A372992

Keyword

nonn

Author

Clark Kimberling, Jul 09 2024

Status

approved