Theta series of hexagonal net with respect to midpoint of edge.

Terms

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