Theta series of 18-dimensional lattice Kappa_18.

Terms

a(0) =1a(1) =0a(2) =6480a(3) =157680a(4) =1596510a(5) =9488016a(6) =40681440a(7) =140492880a(8) =406046520a(9) =1047312720a(10) =2426695200a(11) =5208293520a(12) =10421250750a(13) =19873356480a(14) =35716191840a(15) =62355291696a(16) =104234541390a(17) =169488573120a(18) =267064691760a(19) =413777075760a(20) =619573504896a(21) =920235334320