Av(132)
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Generating Function
\(\displaystyle \frac{1-\sqrt{1-4 x}}{2 x}\)
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Counting Sequence
1, 1, 2, 5, 14, 42, 132, 429, 1430, 4862, 16796, 58786, 208012, 742900, 2674440, ...
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Implicit Equation for the Generating Function
\(\displaystyle x F \left(x \right)^{2}-F \! \left(x \right)+1 = 0\)
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Recurrence
\(\displaystyle a \! \left(0\right) = 1\)
\(\displaystyle a \! \left(n +1\right) = \frac{2 \left(1+2 n \right) a \! \left(n \right)}{n +2}, \quad n \geq 1\)
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This specification was found using the strategy pack "Point Placements" and has 5 rules.

Found on May 17, 2021.

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\(\begin{align*} F_{0}\! \left(x \right) &= F_{1}\! \left(x \right)+F_{2}\! \left(x \right)\\ F_{1}\! \left(x \right) &= 1\\ F_{2}\! \left(x \right) &= F_{3}\! \left(x \right)\\ F_{3}\! \left(x \right) &= F_{0} \left(x \right)^{2} F_{4}\! \left(x \right)\\ F_{4}\! \left(x \right) &= x\\ \end{align*}\)