A020478 - cp's OEIS frontend

A020478 Number of singular 2 X 2 matrices over Z(n) (i.e., with determinant = 0).

n	a(n)
1	1
2	10
3	33
4	88
5	145
6	330
7	385
8	736
9	945
10	1450
11	1441
12	2904
13	2353
14	3850
15	4785
16	6016
17	5185
18	9450
19	7201
20	12760
21	12705
22	14410
23	12673
24	24288
25	18625
26	23530
27	26001
28	33880
29	25201
30	47850
31	30721
32	48640
33	47553
34	51850
35	55825
36	83160
37	51985
38	72010
39	77649
40	106720

[1, 10, 33, 88, 145, 330, 385, 736, 945, 1450, 1441, 2904, 2353, 3850, 4785, 6016, 5185, 9450, 7201, 12760, 12705, 14410, 12673, 24288, 18625, 23530, 26001, 33880, 25201, 47850, 30721, 48640, 47553, 51850, 55825, 83160, 51985, 72010, 77649, 106720]

cp's OEIS Frontend

A020478 Number of singular 2 X 2 matrices over Z(n) (i.e., with determinant = 0).

Table of values

List of values