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

Terms

a(0) =0a(1) =40a(2) =168a(3) =1056a(4) =2080a(5) =6120a(6) =9576a(7) =20608a(8) =28800a(9) =52200a(10) =68200a(11) =110880a(12) =138528a(13) =208936a(14) =252840a(15) =360960a(16) =426496a(17) =583848a(18) =677160a(19) =896800a(20) =1024800a(21) =1321320a(22) =1491688a(23) =1881216a(24) =2102400a(25) =2602600a(26) =2883816a(27) =3513888a(28) =3865120a(29) =4645800