Talk:Catalan numbers/Pascal's triangle

From Rosetta Code
Revision as of 14:07, 9 November 2015 by rosettacode>G.Brougnard (dead link)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

extracting Catalan numbers from Pascal's triangle

As I understand this task's requirements, the Catalan numbers are to be extracted from Pascal's triangle (and therefore, not be directly computed via binomial coefficients or some other means).   Should programming solutions that don't extract Catalan numbers from Pascal's triangle be flagged as incorrect? -- Gerard Schildberger (talk) 18:50, 20 October 2014 (UTC)

  • The task description references Both references to the Pascal triangle are like the first one, which observes in effect that the Catalan numbers can be computed as C(2n;n) - C(2n; n-1). Therefore it seems to me that the question asked by Gerard Shildberger Schildberger is ill-framed. That is, specific equations using binomial coefficients are admissible if their connection with Pascal's triangle is established. Peak (talk) 19:14, 20 October 2014 (UTC)
I don't know how to frame my question other than how I phrased it.   However, I've added a REXX version that computes Catalan numbers using binomial coefficients.   If binomial coefficients are OK to use, then why was the phrase used   ... extracting them from Pascal's triangle?   Using binomial coefficients are of course, much cleaner/simpler/faster than computing elements of Pascal's triangle. -- Gerard Schildberger (talk) 21:32, 20 October 2014 (UTC)

--G.Brougnard (talk) 14:07, 9 November 2015 (UTC)