Theta series of f.c.c. lattice with respect to triangle.

Terms

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