length 2: 12, 21
length 3: 123, 213, 231, 312, 321
length 4: 1234, 2134, 2314, 2341, 3124, 3214, 3241, 3421, 4123, 4213, 4312, 4321
length 5: 12345, 21345, 23145, 23415, 23451, 31245, 32145, 32415, 32451, 34215, 34251, 34521, 41235, 42135, 43125, 43215, 43251, 43521, 45321, 51234, 52134, 53124, 53214, 54123, 54213, 54312, 54321
$\mathcal{A}$ = Av(132, 3412, 4231)
$\operatorname{F_{11}}{\left (x \right )} = \operatorname{F_{10}}{\left (x \right )} + \operatorname{F_{5}}{\left (x \right )}$
$\operatorname{F_{5}}{\left (x \right )} = 1$
$\operatorname{F_{10}}{\left (x \right )} = \operatorname{F_{6}}{\left (x \right )} + \operatorname{F_{9}}{\left (x \right )}$
$\operatorname{F_{6}}{\left (x \right )} = - \frac{x}{x - 1}$
$\operatorname{F_{9}}{\left (x \right )} = \operatorname{F_{7}}{\left (x \right )} + \operatorname{F_{8}}{\left (x \right )}$
$\operatorname{F_{7}}{\left (x \right )} = - \frac{x^{2}}{\left(- 2 x + 1\right) \left(x - 1\right)}$
$\operatorname{F_{8}}{\left (x \right )} = \frac{x^{3}}{\left(- 2 x + 1\right) \left(x - 1\right)^{2}}$