A277085 - cp's OEIS frontend

A277085 Irregular triangle read by rows: T(n,k) = number of size k subsets of S_n that remain unchanged by a rotation of 90 degrees.

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	0
6	1
7	1
8	0
9	1
10	0
11	1
12	0
13	1
14	1
15	2
16	4
17	6
18	10
19	14
20	20
21	26
22	31
23	36
24	40
25	44
26	44
27	44
28	40
29	36
30	31
31	26
32	20
33	14
34	10
35	6
36	4
37	2
38	1
39	1
40	2
41	4
42	6
43	34
44	62
45	116
46	170
47	547
48	924
49	1624
50	2324
51	5572
52	8820
53	14616
54	20412
55	40509
56	60606
57	95004
58	129402
59	224406
60	319410

[1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 2, 4, 6, 10, 14, 20, 26, 31, 36, 40, 44, 44, 44, 40, 36, 31, 26, 20, 14, 10, 6, 4, 2, 1, 1, 2, 4, 6, 34, 62, 116, 170, 547, 924, 1624, 2324, 5572, 8820, 14616, 20412, 40509, 60606, 95004, 129402, 224406, 319410]

cp's OEIS Frontend

A277085 Irregular triangle read by rows: T(n,k) = number of size k subsets of S_n that remain unchanged by a rotation of 90 degrees.

Table of values

List of values