Av(1234, 1243, 1324, 1342, 2134, 2341, 4123)
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Generating Function
\(\displaystyle \frac{-\left(x^{2}+x -1\right) \left(-1+x \right)^{3} \sqrt{1-4 x}-2 x^{7}-x^{5}-x^{3}+5 x^{2}-4 x +1}{2 x \left(x^{2}+x -1\right) \left(-1+x \right)^{3}}\)
Counting Sequence
1, 1, 2, 6, 17, 49, 145, 451, 1465, 4916, 16878, 58910, 208200, 743187, 2674882, ...
Implicit Equation for the Generating Function
\(\displaystyle x \left(x^{2}+x -1\right)^{2} \left(-1+x \right)^{6} F \left(x \right)^{2}+\left(x^{2}+x -1\right) \left(2 x^{7}+x^{5}+x^{3}-5 x^{2}+4 x -1\right) \left(-1+x \right)^{3} F \! \left(x \right)+x^{13}+x^{11}+x^{10}-3 x^{9}-2 x^{8}+18 x^{7}-34 x^{6}+17 x^{5}+24 x^{4}-41 x^{3}+26 x^{2}-8 x +1 = 0\)
Recurrence
\(\displaystyle a \! \left(0\right) = 1\)
\(\displaystyle a \! \left(1\right) = 1\)
\(\displaystyle a \! \left(2\right) = 2\)
\(\displaystyle a \! \left(3\right) = 6\)
\(\displaystyle a \! \left(4\right) = 17\)
\(\displaystyle a \! \left(5\right) = 49\)
\(\displaystyle a \! \left(6\right) = 145\)
\(\displaystyle a \! \left(7\right) = 451\)
\(\displaystyle a \! \left(8\right) = 1465\)
\(\displaystyle a \! \left(9\right) = 4916\)
\(\displaystyle a \! \left(10\right) = 16878\)
\(\displaystyle a \! \left(n +5\right) = \frac{2 \left(2 n +1\right) a \! \left(n \right)}{n +6}+\frac{\left(10+7 n \right) a \! \left(n +1\right)}{n +6}-\frac{2 \left(3 n +8\right) a \! \left(n +2\right)}{n +6}-\frac{\left(7 n +24\right) a \! \left(n +3\right)}{n +6}+\frac{2 \left(3 n +14\right) a \! \left(n +4\right)}{n +6}-\frac{3 n^{3}-35 n^{2}+44 n +64}{2 \left(n +6\right)}, \quad n \geq 11\)

This specification was found using the strategy pack "Requirement Placements Tracked Fusion" and has 63 rules.

Found on July 23, 2021.

Finding the specification took 11 seconds.

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\(\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_{9}\! \left(x \right)\\ F_{4}\! \left(x \right) &= F_{38}\! \left(x \right)+F_{5}\! \left(x \right)\\ F_{5}\! \left(x \right) &= F_{10}\! \left(x \right)+F_{6}\! \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_{6}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{9}\! \left(x \right) &= x\\ F_{10}\! \left(x \right) &= F_{11}\! \left(x \right)+F_{18}\! \left(x \right)\\ F_{11}\! \left(x \right) &= F_{12}\! \left(x \right)\\ F_{12}\! \left(x \right) &= F_{13}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{13}\! \left(x \right) &= F_{14}\! \left(x \right)+F_{15}\! \left(x \right)\\ F_{14}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{9}\! \left(x \right)\\ F_{15}\! \left(x \right) &= F_{11}\! \left(x \right)+F_{16}\! \left(x \right)\\ F_{16}\! \left(x \right) &= F_{17}\! \left(x \right)\\ F_{17}\! \left(x \right) &= F_{11}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{18}\! \left(x \right) &= F_{19}\! \left(x \right)+F_{20}\! \left(x \right)+F_{33}\! \left(x \right)\\ F_{19}\! \left(x \right) &= 0\\ F_{20}\! \left(x \right) &= F_{21}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{21}\! \left(x \right) &= F_{22}\! \left(x \right)+F_{26}\! \left(x \right)\\ F_{22}\! \left(x \right) &= F_{23}\! \left(x \right)+F_{7}\! \left(x \right)\\ F_{23}\! \left(x \right) &= F_{24}\! \left(x \right)\\ F_{24}\! \left(x \right) &= F_{25}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{25}\! \left(x \right) &= F_{23}\! \left(x \right)+F_{9}\! \left(x \right)\\ F_{26}\! \left(x \right) &= F_{18}\! \left(x \right)+F_{27}\! \left(x \right)\\ F_{27}\! \left(x \right) &= F_{28}\! \left(x \right)\\ F_{28}\! \left(x \right) &= F_{29}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{29}\! \left(x \right) &= F_{30}\! \left(x \right)+F_{32}\! \left(x \right)\\ F_{30}\! \left(x \right) &= F_{31}\! \left(x \right)\\ F_{31}\! \left(x \right) &= F_{7}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{32}\! \left(x \right) &= F_{28}\! \left(x \right)\\ F_{33}\! \left(x \right) &= F_{34}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{34}\! \left(x \right) &= F_{35}\! \left(x \right)+F_{7}\! \left(x \right)\\ F_{35}\! \left(x \right) &= F_{19}\! \left(x \right)+F_{33}\! \left(x \right)+F_{36}\! \left(x \right)\\ F_{36}\! \left(x \right) &= F_{37}\! \left(x \right) F_{9}\! \left(x \right)\\ F_{37}\! \left(x \right) &= F_{35}\! \left(x \right)+F_{7}\! \left(x \right)\\ F_{38}\! \left(x \right) &= F_{39}\! \left(x \right)\\ F_{39}\! \left(x \right) &= F_{40}\! \left(x , 1\right)\\ F_{40}\! \left(x , y\right) &= F_{41}\! \left(x , y\right)\\ F_{41}\! \left(x , y\right) &= F_{42}\! \left(x , y\right)\\ F_{42}\! \left(x , y\right) &= F_{43}\! \left(x , y\right) F_{52}\! \left(x , y\right) F_{9}\! \left(x \right)\\ F_{43}\! \left(x , y\right) &= F_{44}\! \left(x , y\right)+F_{62}\! \left(x , y\right)\\ F_{44}\! \left(x , y\right) &= F_{34}\! \left(x \right)+F_{45}\! \left(x , y\right)\\ F_{45}\! \left(x , y\right) &= F_{46}\! \left(x , y\right)+F_{53}\! \left(x , y\right)\\ F_{46}\! \left(x , y\right) &= F_{47}\! \left(x , y\right)\\ F_{47}\! \left(x , y\right) &= F_{48}\! \left(x , y\right) F_{9}\! \left(x \right)\\ F_{48}\! \left(x , y\right) &= F_{46}\! \left(x , y\right)+F_{49}\! \left(x , y\right)\\ F_{49}\! \left(x , y\right) &= F_{50}\! \left(x , y\right)\\ F_{50}\! \left(x , y\right) &= F_{51}\! \left(x , y\right) F_{52}\! \left(x , y\right)\\ F_{51}\! \left(x , y\right) &= y x\\ F_{52}\! \left(x , y\right) &= F_{1}\! \left(x \right)+F_{49}\! \left(x , y\right)\\ F_{53}\! \left(x , y\right) &= 2 F_{19}\! \left(x \right)+F_{54}\! \left(x , y\right)+F_{61}\! \left(x , y\right)\\ F_{54}\! \left(x , y\right) &= F_{55}\! \left(x , y\right) F_{9}\! \left(x \right)\\ F_{55}\! \left(x , y\right) &= F_{53}\! \left(x , y\right)+F_{56}\! \left(x , y\right)\\ F_{56}\! \left(x , y\right) &= F_{19}\! \left(x \right)+F_{57}\! \left(x , y\right)+F_{59}\! \left(x , y\right)\\ F_{57}\! \left(x , y\right) &= F_{51}\! \left(x , y\right) F_{58}\! \left(x , y\right)\\ F_{58}\! \left(x , y\right) &= F_{56}\! \left(x , y\right)+F_{7}\! \left(x \right)\\ F_{59}\! \left(x , y\right) &= F_{60}\! \left(x , y\right) F_{9}\! \left(x \right)\\ F_{60}\! \left(x , y\right) &= F_{49}\! \left(x , y\right)+F_{56}\! \left(x , y\right)\\ F_{61}\! \left(x , y\right) &= F_{45}\! \left(x , y\right) F_{9}\! \left(x \right)\\ F_{62}\! \left(x , y\right) &= \frac{y F_{41}\! \left(x , y\right)-F_{41}\! \left(x , 1\right)}{-1+y}\\ \end{align*}\)