Theta series of hexagonal close-packing.

Terms

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