A090806 - cp's OEIS frontend

A090806 Triangular array read by rows: T(n,k) (n >= 2, 1 <= k <= n) = number of partitions of k white balls and n-k black balls in which each part has at least one ball of each color. Also limit of the joint major-index / inversion polynomial for permutations of n elements, as n becomes infinite.

n	a(n)
2	1
3	1
4	1
5	1
6	2
7	1
8	1
9	2
10	2
11	1
12	1
13	3
14	4
15	3
16	1
17	1
18	3
19	5
20	5
21	3
22	1
23	1
24	4
25	7
26	9
27	7
28	4
29	1
30	1
31	4
32	9
33	12
34	12
35	9
36	4
37	1
38	1
39	5
40	11
41	17
42	20
43	17
44	11
45	5
46	1
47	1
48	5
49	13
50	22
51	28
52	28
53	22
54	13
55	5
56	1
57	1
58	6
59	16
60	29
61	40
62	45
63	40
64	29
65	16
66	6
67	1
68	1
69	6
70	18
71	35
72	53
73	64
74	64
75	53
76	35
77	18
78	6
79	1
80	1
81	7
82	21
83	44
84	70
85	91
86	100
87	91

[1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 4, 3, 1, 1, 3, 5, 5, 3, 1, 1, 4, 7, 9, 7, 4, 1, 1, 4, 9, 12, 12, 9, 4, 1, 1, 5, 11, 17, 20, 17, 11, 5, 1, 1, 5, 13, 22, 28, 28, 22, 13, 5, 1, 1, 6, 16, 29, 40, 45, 40, 29, 16, 6, 1, 1, 6, 18, 35, 53, 64, 64, 53, 35, 18, 6, 1, 1, 7, 21, 44, 70, 91, 100, 91]

cp's OEIS Frontend

A090806 Triangular array read by rows: T(n,k) (n >= 2, 1 <= k <= n) = number of partitions of k white balls and n-k black balls in which each part has at least one ball of each color. Also limit of the joint major-index / inversion polynomial for permutations of n elements, as n becomes infinite.

Table of values

List of values

n	a(n)
2	1
3	1
4	1
5	1
6	2
7	1
8	1
9	2
10	2
11	1
12	1
13	3
14	4
15	3
16	1
17	1
18	3
19	5
20	5
21	3
22	1
23	1
24	4
25	7
26	9
27	7
28	4
29	1
30	1
31	4
32	9
33	12
34	12
35	9
36	4
37	1
38	1
39	5
40	11
41	17
42	20
43	17
44	11
45	5
46	1
47	1
48	5
49	13
50	22
51	28
52	28
53	22
54	13
55	5
56	1
57	1
58	6
59	16
60	29
61	40
62	45
63	40
64	29
65	16
66	6
67	1
68	1
69	6
70	18
71	35
72	53
73	64
74	64
75	53
76	35
77	18
78	6
79	1
80	1
81	7
82	21
83	44
84	70
85	91
86	100
87	91

n	a(n)
2	1
3	1
4	1
5	1
6	2
7	1
8	1
9	2
10	2
11	1
12	1
13	3
14	4
15	3
16	1
17	1
18	3
19	5
20	5
21	3
22	1
23	1
24	4
25	7
26	9
27	7
28	4
29	1
30	1
31	4
32	9
33	12
34	12
35	9
36	4
37	1
38	1
39	5
40	11
41	17
42	20
43	17
44	11
45	5
46	1
47	1
48	5
49	13
50	22
51	28
52	28
53	22
54	13
55	5
56	1
57	1
58	6
59	16
60	29
61	40
62	45
63	40
64	29
65	16
66	6
67	1
68	1
69	6
70	18
71	35
72	53
73	64
74	64
75	53
76	35
77	18
78	6
79	1
80	1
81	7
82	21
83	44
84	70
85	91
86	100
87	91

n	a(n)
2	1
3	1
4	1
5	1
6	2
7	1
8	1
9	2
10	2
11	1
12	1
13	3
14	4
15	3
16	1
17	1
18	3
19	5
20	5
21	3
22	1
23	1
24	4
25	7
26	9
27	7
28	4
29	1
30	1
31	4
32	9
33	12
34	12
35	9
36	4
37	1
38	1
39	5
40	11
41	17
42	20
43	17
44	11
45	5
46	1
47	1
48	5
49	13
50	22
51	28
52	28
53	22
54	13
55	5
56	1
57	1
58	6
59	16
60	29
61	40
62	45
63	40
64	29
65	16
66	6
67	1
68	1
69	6
70	18
71	35
72	53
73	64
74	64
75	53
76	35
77	18
78	6
79	1
80	1
81	7
82	21
83	44
84	70
85	91
86	100
87	91