Number of 2 X 2 matrices having all terms in {1,...,n} and determinant >=3n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =8a(5) =38a(6) =122a(7) =284a(8) =589a(9) =1080a(10) =1848a(11) =2933a(12) =4515a(13) =6577a(14) =9366a(15) =12888a(16) =17444a(17) =22928a(18) =29864a(19) =37986a(20) =48057a(21) =59656a(22) =73413a(23) =89307a(24) =108002a(25) =129068a(26) =153386a(27) =180636a(28) =212111a(29) =246683