Catalan numbers: Difference between revisions

The first method:

<lang factor>USING: kernel math math.combinatorics prettyprint ;

: catalan ( n -- n ) [ 1 + recip ] [ 2 * ] [ nCk * ] tri ;

15 [ catalan . ] each-integer</lang>

{{out}}

<pre>

1

1

2

5

14

42

132

429

1430

4862

16796

58786

208012

742900

2674440

</pre>

This is the last method, memoized by using arrays.