Theta series of A_21 lattice.

Terms

a(0) =1a(1) =462a(2) =43890a(3) =1501500a(4) =23437722a(5) =198944592a(6) =1114627514a(7) =4828206900a(8) =17160463320a(9) =52574485502a(10) =143000133276a(11) =353652649308a(12) =808266398940