Number of orbits of norm 2n vectors in E_8 lattice.

Terms

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