Number of distinct solutions of sum{i=1..4}(x(2i-1)*x(2i)) = 0 (mod n), with x() only in 2..n-2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =3a(5) =30a(6) =102a(7) =485a(8) =1209a(9) =3622a(10) =7472a(11) =18761a(12) =32668a(13) =68364a(14) =113299a(15) =211048a(16) =315291a(17) =560656a(18) =783765a(19) =1302666a(20) =1793022a(21) =2758386a(22) =3624837a(23) =5631414a(24) =7012350a(25) =10247902a(26) =13024865a(27) =18346867a(28) =22183836a(29) =31716850