Av(1243, 2143, 2314, 3142)
Generating Function
\(\displaystyle -\frac{\left(2 x -1\right) \left(x^{2}-3 x +1\right)}{\left(x -1\right) \left(x^{3}-6 x^{2}+5 x -1\right)}\)
Counting Sequence
1, 1, 2, 6, 20, 67, 222, 729, 2381, 7754, 25214, 81928, 266111, 864202, 2806273, ...
Implicit Equation for the Generating Function
\(\displaystyle \left(x -1\right) \left(x^{3}-6 x^{2}+5 x -1\right) F \! \left(x \right)+\left(2 x -1\right) \left(x^{2}-3 x +1\right) = 0\)
Recurrence
\(\displaystyle a \! \left(0\right) = 1\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 6\)
\(\displaystyle a \! \left(n +3\right) = a \! \left(n \right)-6 a \! \left(n +1\right)+5 a \! \left(n +2\right)+1, \quad n \geq 4\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 6\)
\(\displaystyle a \! \left(n +3\right) = a \! \left(n \right)-6 a \! \left(n +1\right)+5 a \! \left(n +2\right)+1, \quad n \geq 4\)
Explicit Closed Form
\(\displaystyle \frac{\left(42 \,\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}-5 \,\mathrm{I} \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}} \sqrt{3}+42 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}+3 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}\right) \left(\frac{\left(-2 \,\mathrm{I} \sqrt{3}-3\right) \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}}{252}+\frac{\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}}{12}-\frac{\left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}}{12}+2\right)^{-n}}{3528}+\frac{\left(\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}-84 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}-9 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}\right) \left(\frac{\left(5 \,\mathrm{I} \sqrt{3}-3\right) \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}}{504}-\frac{\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}}{12}-\frac{\left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}}{12}+2\right)^{-n}}{3528}+1+\frac{\left(-42 \,\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}+4 \,\mathrm{I} \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}} \sqrt{3}+42 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}+6 \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}\right) \left(\frac{\left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{1}{3}}}{6}+2+\frac{\left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}}{56}-\frac{\mathrm{I} \sqrt{3}\, \left(756+84 \,\mathrm{I} \sqrt{3}\right)^{\frac{2}{3}}}{504}\right)^{-n}}{3528}\)
This specification was found using the strategy pack "Point Placements" and has 59 rules.
Found on January 18, 2022.Finding the specification took 1 seconds.
Copy 59 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_{12}\! \left(x \right) F_{4}\! \left(x \right)\\
F_{4}\! \left(x \right) &= F_{21}\! \left(x \right)+F_{5}\! \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_{12}\! \left(x \right) F_{8}\! \left(x \right)\\
F_{8}\! \left(x \right) &= F_{13}\! \left(x \right)+F_{9}\! \left(x \right)\\
F_{9}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{10}\! \left(x \right)\\
F_{10}\! \left(x \right) &= F_{11}\! \left(x \right)\\
F_{11}\! \left(x \right) &= F_{12}\! \left(x \right) F_{9}\! \left(x \right)\\
F_{12}\! \left(x \right) &= x\\
F_{13}\! \left(x \right) &= F_{14}\! \left(x \right)+F_{6}\! \left(x \right)\\
F_{14}\! \left(x \right) &= F_{15}\! \left(x \right)+F_{16}\! \left(x \right)+F_{20}\! \left(x \right)\\
F_{15}\! \left(x \right) &= 0\\
F_{16}\! \left(x \right) &= F_{12}\! \left(x \right) F_{17}\! \left(x \right)\\
F_{17}\! \left(x \right) &= F_{18}\! \left(x \right)+F_{19}\! \left(x \right)\\
F_{18}\! \left(x \right) &= F_{10}\! \left(x \right)\\
F_{19}\! \left(x \right) &= F_{14}\! \left(x \right)\\
F_{20}\! \left(x \right) &= F_{12}\! \left(x \right) F_{13}\! \left(x \right)\\
F_{21}\! \left(x \right) &= F_{2}\! \left(x \right)+F_{22}\! \left(x \right)\\
F_{22}\! \left(x \right) &= F_{15}\! \left(x \right)+F_{23}\! \left(x \right)+F_{50}\! \left(x \right)\\
F_{23}\! \left(x \right) &= F_{12}\! \left(x \right) F_{24}\! \left(x \right)\\
F_{24}\! \left(x \right) &= F_{25}\! \left(x \right)+F_{29}\! \left(x \right)\\
F_{25}\! \left(x \right) &= F_{10}\! \left(x \right)+F_{26}\! \left(x \right)\\
F_{26}\! \left(x \right) &= F_{27}\! \left(x \right)\\
F_{27}\! \left(x \right) &= F_{12}\! \left(x \right) F_{28}\! \left(x \right)\\
F_{28}\! \left(x \right) &= F_{26}\! \left(x \right)+F_{6}\! \left(x \right)\\
F_{29}\! \left(x \right) &= F_{30}\! \left(x \right)+F_{33}\! \left(x \right)\\
F_{30}\! \left(x \right) &= F_{15}\! \left(x \right)+F_{23}\! \left(x \right)+F_{31}\! \left(x \right)\\
F_{31}\! \left(x \right) &= F_{12}\! \left(x \right) F_{32}\! \left(x \right)\\
F_{32}\! \left(x \right) &= F_{2}\! \left(x \right)+F_{30}\! \left(x \right)\\
F_{33}\! \left(x \right) &= F_{34}\! \left(x \right)\\
F_{34}\! \left(x \right) &= F_{12}\! \left(x \right) F_{35}\! \left(x \right)\\
F_{35}\! \left(x \right) &= F_{36}\! \left(x \right)+F_{49}\! \left(x \right)\\
F_{36}\! \left(x \right) &= F_{37}\! \left(x \right)\\
F_{37}\! \left(x \right) &= F_{12}\! \left(x \right) F_{38}\! \left(x \right)\\
F_{38}\! \left(x \right) &= F_{39}\! \left(x \right)+F_{42}\! \left(x \right)\\
F_{39}\! \left(x \right) &= F_{2}\! \left(x \right)+F_{40}\! \left(x \right)\\
F_{40}\! \left(x \right) &= F_{41}\! \left(x \right)\\
F_{41}\! \left(x \right) &= F_{12}\! \left(x \right) F_{39}\! \left(x \right)\\
F_{42}\! \left(x \right) &= F_{36}\! \left(x \right)+F_{43}\! \left(x \right)\\
F_{43}\! \left(x \right) &= 2 F_{15}\! \left(x \right)+F_{44}\! \left(x \right)+F_{48}\! \left(x \right)\\
F_{44}\! \left(x \right) &= F_{12}\! \left(x \right) F_{45}\! \left(x \right)\\
F_{45}\! \left(x \right) &= F_{46}\! \left(x \right)+F_{47}\! \left(x \right)\\
F_{46}\! \left(x \right) &= F_{40}\! \left(x \right)\\
F_{47}\! \left(x \right) &= F_{43}\! \left(x \right)\\
F_{48}\! \left(x \right) &= F_{12}\! \left(x \right) F_{42}\! \left(x \right)\\
F_{49}\! \left(x \right) &= F_{34}\! \left(x \right)\\
F_{50}\! \left(x \right) &= F_{12}\! \left(x \right) F_{51}\! \left(x \right)\\
F_{51}\! \left(x \right) &= F_{32}\! \left(x \right)+F_{52}\! \left(x \right)\\
F_{52}\! \left(x \right) &= F_{36}\! \left(x \right)+F_{53}\! \left(x \right)\\
F_{53}\! \left(x \right) &= 2 F_{15}\! \left(x \right)+F_{54}\! \left(x \right)+F_{58}\! \left(x \right)\\
F_{54}\! \left(x \right) &= F_{12}\! \left(x \right) F_{55}\! \left(x \right)\\
F_{55}\! \left(x \right) &= F_{56}\! \left(x \right)+F_{57}\! \left(x \right)\\
F_{56}\! \left(x \right) &= F_{30}\! \left(x \right)\\
F_{57}\! \left(x \right) &= F_{53}\! \left(x \right)\\
F_{58}\! \left(x \right) &= F_{12}\! \left(x \right) F_{52}\! \left(x \right)\\
\end{align*}\)