Number of 2 X 2 matrices with all terms in {0,1,...,n} and even trace.

Terms

a(0) =1a(1) =8a(2) =45a(3) =128a(4) =325a(5) =648a(6) =1225a(7) =2048a(8) =3321a(9) =5000a(10) =7381a(11) =10368a(12) =14365a(13) =19208a(14) =25425a(15) =32768a(16) =41905a(17) =52488a(18) =65341a(19) =80000a(20) =97461a(21) =117128a(22) =140185a(23) =165888a(24) =195625a(25) =228488a(26) =266085a(27) =307328a(28) =354061a(29) =405000