Discriminant of lattice A_n of determinant n+1.

Terms

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