A188479 Binomial variation of the Catalan numbers: a(n) = sum( binomial(n-i, i)*a(i)*a(n-1-i), i=0..(n-1) ) with a(0)=1.

1, 1, 2, 4, 12, 40, 156, 700, 3520, 19592, 119992, 801272, 5792464, 45071600, 375615696, 3338063600, 31511918816, 314913425280, 3321357021600, 36868596345056, 429672869359360, 5245439731918784, 66941714022827072, 891387254398818752, 12363478873222765568, 178331546692362644992, 2671094825005048612224

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Mathematica

a[0]=1; a[n_]:=a[n]=Sum[ Binomial[n-i, i] a[i]*a[n-1-i], {i, 0, n-1}]; Table[ a[n], {n, 0, 30}]

Crossrefs

A000108, A001147, A188478

Sequence in context: A215073 A215074 A215070 * A381360 A062962 A033472

Adjacent sequences: A188476 A188477 A188478 * A188480 A188481 A188482

Keyword

nonn,easy

Author

Olivier Gérard, Apr 01 2011

Status

approved