A201058 Numerator of binomial(2n,n)/(2n).

1, 3, 10, 35, 126, 77, 1716, 6435, 24310, 46189, 352716, 676039, 5200300, 10029150, 5170584, 300540195, 1166803110, 756261275, 17672631900, 6892326441, 89709645740, 526024740930, 4116715363800, 2687300306925, 63205303218876, 123979633237026, 973469712824056, 136583760727865, 15033633249770520, 29566145391215356

Offset

1,2

Comments

There is at least one published paper that refers to binomial(2n,n)/(2n) as the Catalan numbers. Of course the Catalan numbers are really A000108.

Links

Table of n, a(n) for n=1..30.

Patrick Dehornoy, On the rotation distance between binary trees, Adv. Math. 223 (2010), no. 4, 1316-1355.

Example

1, 3/2, 10/3, 35/4, 126/5, 77, 1716/7, 6435/8, 24310/9, 46189/5, 352716/11, 676039/6, ...

Mathematica

Numerator[Table[Binomial[2n, n]/(2n), {n, 30}]] (* Harvey P. Dale, Jan 06 2013 *)

Crossrefs

Cf. A000108, A201059.

Sequence in context: A026026 A047037 A339040 * A318113 A216710 A087946

Adjacent sequences: A201055 A201056 A201057 * A201059 A201060 A201061

Keyword

nonn,frac

Author

N. J. A. Sloane, Nov 26 2011

Status

approved