Data:10 41/HOMFLYPT Polynomial

$z^2 a^6+a^6-2 z^4 a^4-4 z^2 a^4-2 a^4+z^6 a^2+3 z^4 a^2+4 z^2 a^2+2 a^2-2 z^4-4 z^2-1+z^2 a^{-2} + a^{-2}$