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

Terms

a(0) =0a(1) =10a(2) =66a(3) =224a(4) =576a(5) =1210a(6) =2290a(7) =3936a(8) =6352a(9) =9722a(10) =14322a(11) =20304a(12) =28080a(13) =37834a(14) =49922a(15) =64704a(16) =82624a(17) =103898a(18) =129170a(19) =158640a(20) =192944a(21) =232554a(22) =278050a(23) =329680a(24) =388368a(25) =454522a(26) =528770a(27) =611680a(28) =704192a(29) =806490