cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

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

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Nov 26 2011

Keywords

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.

Examples

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

Crossrefs

Programs

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

A188669 a(n) = ceiling(binomial(2*n-1,n-1)/n).

Original entry on oeis.org

1, 2, 4, 9, 26, 77, 246, 805, 2702, 9238, 32066, 112674, 400024, 1432736, 5170584, 18783763, 68635478, 252087092, 930138522, 3446163221, 12815663678, 47820430994, 178987624514, 671825076732, 2528212128756, 9536894864387, 36054433808299, 136583760727865, 518401146543812, 1971076359414358, 7506908923471954, 28634752202227978
Offset: 1

Views

Author

Robert Gerbicz and N. J. A. Sloane, Apr 07 2011

Keywords

Comments

A useful lower bound when studying certain problems involving compositions.

Crossrefs

See A201058, A201059 for numerators and denominators without ceiling. - F. Chapoton, Aug 15 2021

Programs

  • Magma
    [Ceiling(Binomial(2*n-1,n-1)/n): n in [1..60]]; // Vincenzo Librandi, Sep 07 2016
  • Mathematica
    Table[Ceiling[Binomial[2 n - 1, n - 1]/n], {n, 35}]  (* Harvey P. Dale, Apr 09 2011 *)
Showing 1-2 of 2 results.