Theta series of Kleinian lattice Z[(1 + sqrt(-7))/ 2] in 1 complex (or 2 real) dimensions.

Terms

a(0) =1a(1) =2a(2) =4a(3) =0a(4) =6a(5) =0a(6) =0a(7) =2a(8) =8a(9) =2a(10) =0a(11) =4a(12) =0a(13) =0a(14) =4a(15) =0a(16) =10a(17) =0a(18) =4a(19) =0a(20) =0a(21) =0a(22) =8a(23) =4a(24) =0a(25) =2a(26) =0a(27) =0a(28) =6a(29) =4