Schröder Numbers and Combinatorial Sequences

Schröder Numbers are integer sequences arising in combinatorial problems, closely related to Catalan numbers. They count lattice paths with specific restrictions and have connections to various combinatorial structures including triangulations and parenthesizations.

8 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

What is the general formula for the Schröder number (S_n)?

  1. \(S_n = \frac{1}{n+1}\binom{2n}{n}\)
  2. \(S_n = \frac{1}{n}\binom{2n+1}{n}\)
  3. \(S_n = \frac{1}{n+2}\binom{2n+2}{n}\)
  4. \(S_n = \frac{1}{n-1}\binom{2n-1}{n}\)
Question 2 Multiple Choice (Single Answer)

What is the value of (S_5)?

  1. 42
  2. 56
  3. 70
  4. 84
Question 3 Multiple Choice (Single Answer)

What is the relationship between Schröder numbers and Catalan numbers (C_n)?

  1. \(S_n = C_n\)
  2. \(S_n = 2C_n\)
  3. \(S_n = C_n + 1\)
  4. \(S_n = C_n - 1\)
Question 4 Multiple Choice (Single Answer)

What is the generating function for the Schröder numbers?

  1. \(F(x) = \frac{1}{1-x-x^2}\)
  2. \(F(x) = \frac{1}{1+x+x^2}\)
  3. \(F(x) = \frac{1}{1-x^2}\)
  4. \(F(x) = \frac{1}{1+x^2}\)
Question 5 Multiple Choice (Single Answer)

What is the asymptotic behavior of the Schröder numbers?

  1. \(S_n \sim \frac{1}{\sqrt{n}}\left(\frac{4}{3}\right)^n\)
  2. \(S_n \sim \frac{1}{\sqrt{n}}\left(\frac{3}{4}\right)^n\)
  3. \(S_n \sim \frac{1}{n}\left(\frac{4}{3}\right)^n\)
  4. \(S_n \sim \frac{1}{n}\left(\frac{3}{4}\right)^n\)
Question 6 Multiple Choice (Single Answer)

What is the number of ways to triangulate a convex (n)-gon?

  1. \(S_n\)
  2. \(C_n\)
  3. \(S_n + C_n\)
  4. \(S_n - C_n\)
Question 7 Multiple Choice (Single Answer)

What is the number of ways to parenthesize a product of (n) factors?

  1. \(S_n\)
  2. \(C_n\)
  3. \(S_n + C_n\)
  4. \(S_n - C_n\)
Question 8 Multiple Choice (Single Answer)

What is the number of ways to construct a binary tree with (n) internal nodes?

  1. \(S_n\)
  2. \(C_n\)
  3. \(S_n + C_n\)
  4. \(S_n - C_n\)