Theta series of hexagonal lattice A_2 with respect to deep hole divided by 3.

Terms

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