z 18 + 17 z 16 + 120 z 14 + 455 z 12 + 1001 z 10 + 1287 z 8 + 924 z 6 + 330 z 4 + 45 z 2 + 1 {\displaystyle z^{18}+17z^{16}+120z^{14}+455z^{12}+1001z^{10}+1287z^{8}+924z^{6}+330z^{4}+45z^{2}+1}
