/ 2 \
\polygamma (0, 1 + x) + polygamma(1, 1 + x)/*Gamma(1 + x)
$$\left(\operatorname{polygamma}^{2}{\left(0,x + 1 \right)} + \operatorname{polygamma}{\left(1,x + 1 \right)}\right) \Gamma\left(x + 1\right)$$
/ 3 \
\polygamma (0, 1 + x) + 3*polygamma(0, 1 + x)*polygamma(1, 1 + x) + polygamma(2, 1 + x)/*Gamma(1 + x)
$$\left(\operatorname{polygamma}^{3}{\left(0,x + 1 \right)} + 3 \operatorname{polygamma}{\left(0,x + 1 \right)} \operatorname{polygamma}{\left(1,x + 1 \right)} + \operatorname{polygamma}{\left(2,x + 1 \right)}\right) \Gamma\left(x + 1\right)$$