Av(132, 2134, 2314, 2341, 3124, 3214, 3241, 3412, 4123, 4312, 4321)
Generating Function
      
        \(\displaystyle \frac{3 x^{5}+x^{4}-3 x^{3}-x^{2}-1}{x -1}\)
      
      
    Counting Sequence
      
        1, 1, 2, 5, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
      
      
    
        Implicit Equation for the Generating Function
        
      
      
      
        \(\displaystyle \left(1-x \right) F \! \left(x \right)+3 x^{5}+x^{4}-3 x^{3}-x^{2}-1 = 0\)
      
      
      
    Recurrence
      
        
        
        \(\displaystyle a \! \left(0\right) = 1\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 5\)
\(\displaystyle a \! \left(4\right) = 4\)
\(\displaystyle a \! \left(5\right) = 1\)
\(\displaystyle a \! \left(n \right) = 1, \quad n \geq 6\)
      
    \(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 5\)
\(\displaystyle a \! \left(4\right) = 4\)
\(\displaystyle a \! \left(5\right) = 1\)
\(\displaystyle a \! \left(n \right) = 1, \quad n \geq 6\)
Explicit Closed Form
      
        
        \(\displaystyle \left\{\begin{array}{cc}2 & n =2 \\ 5 & n =3 \\ 4 & n =4 \\ 1 & \text{otherwise}  \end{array}\right.\)
      
      
    This specification was found using the strategy pack "Point Placements" and has 25 rules.
Found on January 18, 2022.Finding the specification took 0 seconds.
            
              Copy 25 equations to clipboard:
            
            
            
            
            
            
            
            
            
            
        
              \(\begin{align*}
                
                F_{0}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{2}\! \left(x \right)\\
                
                F_{1}\! \left(x \right) &= 1\\
                
                F_{2}\! \left(x \right) &= F_{3}\! \left(x \right)\\
                
                F_{3}\! \left(x \right) &= F_{4}\! \left(x \right) F_{5}\! \left(x \right)\\
                
                F_{4}\! \left(x \right) &= x\\
                
                F_{5}\! \left(x \right) &= F_{6}\! \left(x \right)+F_{9}\! \left(x \right)\\
                
                F_{6}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{7}\! \left(x \right)\\
                
                F_{7}\! \left(x \right) &= F_{8}\! \left(x \right)\\
                
                F_{8}\! \left(x \right) &= F_{4}\! \left(x \right) F_{6}\! \left(x \right)\\
                
                F_{9}\! \left(x \right) &= F_{10}\! \left(x \right)+F_{19}\! \left(x \right)\\
                
                F_{10}\! \left(x \right) &= F_{11}\! \left(x \right)\\
                
                F_{11}\! \left(x \right) &= F_{12}\! \left(x \right) F_{4}\! \left(x \right)\\
                
                F_{12}\! \left(x \right) &= F_{13}\! \left(x \right)+F_{14}\! \left(x \right)\\
                
                F_{13}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{4}\! \left(x \right)\\
                
                F_{14}\! \left(x \right) &= F_{15}\! \left(x \right)+F_{4}\! \left(x \right)\\
                
                F_{15}\! \left(x \right) &= F_{16}\! \left(x \right)+F_{17}\! \left(x \right)+F_{18}\! \left(x \right)\\
                
                F_{16}\! \left(x \right) &= 0\\
                
                F_{17}\! \left(x \right) &= x^{2}\\
                
                F_{18}\! \left(x \right) &= x^{2}\\
                
                F_{19}\! \left(x \right) &= F_{16}\! \left(x \right)+F_{20}\! \left(x \right)+F_{22}\! \left(x \right)\\
                
                F_{20}\! \left(x \right) &= F_{21}\! \left(x \right) F_{4}\! \left(x \right)\\
                
                F_{21}\! \left(x \right) &= F_{4}\! \left(x \right)\\
                
                F_{22}\! \left(x \right) &= F_{23}\! \left(x \right) F_{4}\! \left(x \right)\\
                
                F_{23}\! \left(x \right) &= F_{24}\! \left(x \right)\\
                
                F_{24}\! \left(x \right) &= F_{13}\! \left(x \right) F_{4}\! \left(x \right)\\
                
                \end{align*}\)