A211157 - cp's OEIS frontend

A211157 Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and positive even determinant.

n	a(n)
1	4
2	164
3	528
4	1968
5	3844
6	8836
7	14144
8	26176
9	37540
10	61188
11	82192
12	123120
13	157924
14	223268
15	276608
16	374272
17	452420
18	591524
19	700752
20	891760
21	1038980
22	1293700
23	1487744
24	1818112
25	2067172

[4, 164, 528, 1968, 3844, 8836, 14144, 26176, 37540, 61188, 82192, 123120, 157924, 223268, 276608, 374272, 452420, 591524, 700752, 891760, 1038980, 1293700, 1487744, 1818112, 2067172]

cp's OEIS Frontend

A211157 Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and positive even determinant.

Table of values

List of values