Data:L11n409/HOMFLYPT Polynomial

$-z^6+3 a^2 z^4+z^4 a^{-2} -3 z^4-2 a^4 z^2+7 a^2 z^2+z^2 a^{-2} -6 z^2-2 a^4+6 a^2+2 a^{-2} -6+a^2 z^{-2} + a^{-2} z^{-2} -2 z^{-2}$