A287020 - cp's OEIS frontend

A287020 Triangle read by rows: T(n,m) is the number of inequivalent n X m matrices under action of the Klein group, with one-fourth each of 1s, 2s, 3s and 4s (ordered occurrences rounded up/down if n*m != 0 mod 4).

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	6
6	1
7	1
8	46
9	1926
10	1
11	12
12	648
13	92544
14	15767640
15	1
16	30
17	6312
18	3943710
19	2933201376
20	2061379857600
21	1
22	90
23	92400
24	192994200
25	577186150464
26	1605824110657800
27	5363188066566330000
28	1
29	318
30	1051140
31	10266445476
32	118129589107200
33	1340797019145183600

[1, 1, 1, 1, 1, 6, 1, 1, 46, 1926, 1, 12, 648, 92544, 15767640, 1, 30, 6312, 3943710, 2933201376, 2061379857600, 1, 90, 92400, 192994200, 577186150464, 1605824110657800, 5363188066566330000, 1, 318, 1051140, 10266445476, 118129589107200, 1340797019145183600]

cp's OEIS Frontend

A287020 Triangle read by rows: T(n,m) is the number of inequivalent n X m matrices under action of the Klein group, with one-fourth each of 1s, 2s, 3s and 4s (ordered occurrences rounded up/down if n*m != 0 mod 4).

Table of values

List of values