Number of 2 X 2 matrices with all terms in {0,1,...,n} and (sum of terms) = determinant.

Terms

a(0) =1a(1) =1a(2) =2a(3) =9a(4) =18a(5) =41a(6) =58a(7) =97a(8) =130a(9) =185a(10) =226a(11) =313a(12) =354a(13) =457a(14) =538a(15) =649a(16) =738a(17) =889a(18) =954a(19) =1145a(20) =1266a(21) =1449a(22) =1578a(23) =1809a(24) =1930a(25) =2177a(26) =2362a(27) =2609a(28) =2770a(29) =3129