Bosonic string states.

Terms

a(0) =1a(1) =-1a(2) =0a(3) =0a(4) =1a(5) =0a(6) =1a(7) =0a(8) =2a(9) =0a(10) =3a(11) =1a(12) =6a(13) =2a(14) =9a(15) =6a(16) =16