Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and determinant >= 3n.

Terms

a(0) =0a(1) =20a(2) =184a(3) =804a(4) =2284a(5) =5408a(6) =10780a(7) =20084a(8) =33664a(9) =53840a(10) =81124a(11) =119156a(12) =167872a(13) =231096a(14) =309816a(15) =409128a(16) =527088a(17) =673112a(18) =842776a(19) =1049352a(20) =1285760a(21) =1561932a(22) =1879908a(23) =2247884a(24) =2662000a(25) =3134360a(26) =3662256a(27) =4264796a(28) =4926892a(29) =5673180