A238888 - cp's OEIS frontend

A238888 Number A(n,k) of self-inverse permutations p on [n] with displacement of elements restricted by k: |p(i)-i| <= k, square array A(n,k), n>=0, k>=0, read by antidiagonals.

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	2
9	1
10	1
11	1
12	2
13	3
14	1
15	1
16	1
17	2
18	4
19	5
20	1
21	1
22	1
23	2
24	4
25	8
26	8
27	1
28	1
29	1
30	2
31	4
32	10
33	15
34	13
35	1
36	1
37	1
38	2
39	4
40	10
41	22
42	29
43	21
44	1
45	1
46	1
47	2
48	4
49	10
50	26
51	48
52	56
53	34
54	1
55	1
56	1
57	2
58	4
59	10
60	26
61	66
62	103
63	108
64	55
65	1
66	1
67	1
68	2
69	4
70	10
71	26
72	76
73	158
74	225
75	208
76	89
77	1
78	1
79	1
80	2
81	4
82	10
83	26
84	76
85	206
86	376
87	492
88	401
89	144
90	1

[1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 1, 2, 4, 5, 1, 1, 1, 2, 4, 8, 8, 1, 1, 1, 2, 4, 10, 15, 13, 1, 1, 1, 2, 4, 10, 22, 29, 21, 1, 1, 1, 2, 4, 10, 26, 48, 56, 34, 1, 1, 1, 2, 4, 10, 26, 66, 103, 108, 55, 1, 1, 1, 2, 4, 10, 26, 76, 158, 225, 208, 89, 1, 1, 1, 2, 4, 10, 26, 76, 206, 376, 492, 401, 144, 1]

cp's OEIS Frontend

A238888 Number A(n,k) of self-inverse permutations p on [n] with displacement of elements restricted by k: |p(i)-i| <= k, square array A(n,k), n>=0, k>=0, read by antidiagonals.

Table of values

List of values

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	2
9	1
10	1
11	1
12	2
13	3
14	1
15	1
16	1
17	2
18	4
19	5
20	1
21	1
22	1
23	2
24	4
25	8
26	8
27	1
28	1
29	1
30	2
31	4
32	10
33	15
34	13
35	1
36	1
37	1
38	2
39	4
40	10
41	22
42	29
43	21
44	1
45	1
46	1
47	2
48	4
49	10
50	26
51	48
52	56
53	34
54	1
55	1
56	1
57	2
58	4
59	10
60	26
61	66
62	103
63	108
64	55
65	1
66	1
67	1
68	2
69	4
70	10
71	26
72	76
73	158
74	225
75	208
76	89
77	1
78	1
79	1
80	2
81	4
82	10
83	26
84	76
85	206
86	376
87	492
88	401
89	144
90	1

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	2
9	1
10	1
11	1
12	2
13	3
14	1
15	1
16	1
17	2
18	4
19	5
20	1
21	1
22	1
23	2
24	4
25	8
26	8
27	1
28	1
29	1
30	2
31	4
32	10
33	15
34	13
35	1
36	1
37	1
38	2
39	4
40	10
41	22
42	29
43	21
44	1
45	1
46	1
47	2
48	4
49	10
50	26
51	48
52	56
53	34
54	1
55	1
56	1
57	2
58	4
59	10
60	26
61	66
62	103
63	108
64	55
65	1
66	1
67	1
68	2
69	4
70	10
71	26
72	76
73	158
74	225
75	208
76	89
77	1
78	1
79	1
80	2
81	4
82	10
83	26
84	76
85	206
86	376
87	492
88	401
89	144
90	1

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	2
9	1
10	1
11	1
12	2
13	3
14	1
15	1
16	1
17	2
18	4
19	5
20	1
21	1
22	1
23	2
24	4
25	8
26	8
27	1
28	1
29	1
30	2
31	4
32	10
33	15
34	13
35	1
36	1
37	1
38	2
39	4
40	10
41	22
42	29
43	21
44	1
45	1
46	1
47	2
48	4
49	10
50	26
51	48
52	56
53	34
54	1
55	1
56	1
57	2
58	4
59	10
60	26
61	66
62	103
63	108
64	55
65	1
66	1
67	1
68	2
69	4
70	10
71	26
72	76
73	158
74	225
75	208
76	89
77	1
78	1
79	1
80	2
81	4
82	10
83	26
84	76
85	206
86	376
87	492
88	401
89	144
90	1