Av(1243, 1324, 2413, 2431, 3142)
Generating Function
\(\displaystyle -\frac{\left(-1+\sqrt{1-4 x}\right) \left(x^{3}-5 x^{2}+4 x -1\right)}{2 x \left(2 x -1\right) \left(x -1\right)^{2}}\)
Counting Sequence
1, 1, 2, 6, 19, 59, 182, 568, 1812, 5927, 19853, 67883, 236107, 832705, 2970165, ...
Implicit Equation for the Generating Function
\(\displaystyle x \left(2 x -1\right)^{2} \left(x -1\right)^{4} F \left(x
\right)^{2}-\left(2 x -1\right) \left(x^{3}-5 x^{2}+4 x -1\right) \left(x -1\right)^{2} F \! \left(x \right)+\left(x^{3}-5 x^{2}+4 x -1\right)^{2} = 0\)
Recurrence
\(\displaystyle a \! \left(0\right) = 1\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 6\)
\(\displaystyle a \! \left(4\right) = 19\)
\(\displaystyle a \! \left(5\right) = 59\)
\(\displaystyle a \! \left(6\right) = 182\)
\(\displaystyle a \! \left(n +6\right) = -\frac{4 \left(2 n +1\right) a \! \left(n \right)}{n +7}+\frac{6 \left(9 n +17\right) a \! \left(1+n \right)}{n +7}-\frac{\left(109 n +296\right) a \! \left(n +2\right)}{n +7}+\frac{5 \left(20 n +73\right) a \! \left(n +3\right)}{n +7}-\frac{\left(47 n +221\right) a \! \left(n +4\right)}{n +7}+\frac{\left(64+11 n \right) a \! \left(n +5\right)}{n +7}+\frac{1}{n +7}, \quad n \geq 7\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 6\)
\(\displaystyle a \! \left(4\right) = 19\)
\(\displaystyle a \! \left(5\right) = 59\)
\(\displaystyle a \! \left(6\right) = 182\)
\(\displaystyle a \! \left(n +6\right) = -\frac{4 \left(2 n +1\right) a \! \left(n \right)}{n +7}+\frac{6 \left(9 n +17\right) a \! \left(1+n \right)}{n +7}-\frac{\left(109 n +296\right) a \! \left(n +2\right)}{n +7}+\frac{5 \left(20 n +73\right) a \! \left(n +3\right)}{n +7}-\frac{\left(47 n +221\right) a \! \left(n +4\right)}{n +7}+\frac{\left(64+11 n \right) a \! \left(n +5\right)}{n +7}+\frac{1}{n +7}, \quad n \geq 7\)
This specification was found using the strategy pack "Point Placements" and has 23 rules.
Found on July 23, 2021.Finding the specification took 2 seconds.
Copy 23 equations to clipboard:
\(\begin{align*}
F_{0}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{2}\! \left(x \right)\\
F_{1}\! \left(x \right) &= 1\\
F_{2}\! \left(x \right) &= F_{3}\! \left(x \right)\\
F_{3}\! \left(x \right) &= F_{4}\! \left(x \right) F_{8}\! \left(x \right)\\
F_{4}\! \left(x \right) &= F_{5}\! \left(x \right)+F_{9}\! \left(x \right)\\
F_{5}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{6}\! \left(x \right)\\
F_{6}\! \left(x \right) &= F_{7}\! \left(x \right)\\
F_{7}\! \left(x \right) &= F_{5} \left(x \right)^{2} F_{8}\! \left(x \right)\\
F_{8}\! \left(x \right) &= x\\
F_{9}\! \left(x \right) &= F_{10}\! \left(x \right)\\
F_{10}\! \left(x \right) &= F_{11}\! \left(x \right) F_{8}\! \left(x \right)\\
F_{11}\! \left(x \right) &= F_{12}\! \left(x \right)+F_{13}\! \left(x \right)\\
F_{12}\! \left(x \right) &= F_{4}\! \left(x \right) F_{5}\! \left(x \right)\\
F_{13}\! \left(x \right) &= F_{14}\! \left(x \right)\\
F_{14}\! \left(x \right) &= F_{18} \left(x \right)^{2} F_{15}\! \left(x \right) F_{20}\! \left(x \right)\\
F_{15}\! \left(x \right) &= F_{16}\! \left(x \right)\\
F_{16}\! \left(x \right) &= F_{17}\! \left(x \right) F_{8}\! \left(x \right)\\
F_{17}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{15}\! \left(x \right)\\
F_{18}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{19}\! \left(x \right)\\
F_{19}\! \left(x \right) &= F_{18}\! \left(x \right) F_{8}\! \left(x \right)\\
F_{20}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{21}\! \left(x \right)\\
F_{21}\! \left(x \right) &= F_{22}\! \left(x \right)\\
F_{22}\! \left(x \right) &= F_{18}\! \left(x \right) F_{20}\! \left(x \right) F_{8}\! \left(x \right)\\
\end{align*}\)