Number of 3 X 3 matrices having all terms in {0,1,...,n} with |det| = 1.

Terms

a(0) =0a(1) =168a(2) =2022a(3) =15090a(4) =53160a(5) =196962a(6) =409956a(7) =1096368a(8) =2062140a(9) =4070796a(10) =6674010a(11) =12603174a(12) =18410352a(13) =31642836a(14) =45306438a(15) =67301682a(16) =93747984a(17) =142196892a(18) =183799392a(19) =267038772a(20) =342684960a(21) =458663640a(22) =582535842a(23) =793793994a(24) =963867732a(25) =1266864846a(26) =1550198598a(27) =1957887150a(28) =2357651670a(29) =3015489714