Number of unimodular 2 X 2 matrices having all terms in {0,1,...,n}.

Terms

a(0) =0a(1) =6a(2) =14a(3) =30a(4) =46a(5) =78a(6) =94a(7) =142a(8) =174a(9) =222a(10) =254a(11) =334a(12) =366a(13) =462a(14) =510a(15) =574a(16) =638a(17) =766a(18) =814a(19) =958a(20) =1022a(21) =1118a(22) =1198a(23) =1374a(24) =1438a(25) =1598a(26) =1694a(27) =1838a(28) =1934a(29) =2158