A224867 - cp's OEIS frontend

A224867 Number T(n,k) of tilings of an n X k rectangle using integer-sided square tiles reduced for symmetry, where the orbits under the symmetry group of the rectangle, D2, have 4 elements; triangle T(n,k), k >= 1, 0 <= n < k, read by columns.

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	0
10	1
11	0
12	0
13	0
14	5
15	21
16	0
17	0
18	0
19	10
20	65
21	440
22	0
23	0
24	0
25	27
26	222
27	1901
28	14508
29	0
30	0
31	0
32	58
33	676
34	7716
35	81119
36	856559

[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 5, 21, 0, 0, 0, 10, 65, 440, 0, 0, 0, 27, 222, 1901, 14508, 0, 0, 0, 58, 676, 7716, 81119, 856559]