Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).

Terms

a(0) =10a(1) =33a(2) =160a(3) =145a(4) =1008a(5) =385a(6) =2560a(7) =2673a(8) =7120a(9) =1441a(10) =16128a(11) =2353a(12) =26320a(13) =27585a(14) =40960a(15) =5185a(16) =81648a(17) =7201a(18) =113920a(19) =97713a(20) =155056a(21) =12673a(22) =258048a(23) =90625a(24) =299728a(25) =216513a(26) =421120a(27) =25201a(28) =671760a(29) =30721