A381899 - cp's OEIS frontend

A381899 Irregular triangular array read by rows. T(n,k) is the number of length n words x on {0,1} such that I(x) + W(x)*(n-W(x)) = k, where I(x) is the number of inversions in x and W(x) is the number of 1's in x, n >= 0, 0 <= k <= floor(n^2/2).

n	a(n)
0	1
1	2
2	2
3	1
4	1
5	2
6	0
7	2
8	2
9	2
10	2
11	0
12	0
13	2
14	3
15	3
16	4
17	1
18	1
19	2
20	0
21	0
22	0
23	2
24	2
25	4
26	4
27	6
28	4
29	4
30	2
31	2
32	2
33	0
34	0
35	0
36	0
37	2
38	2
39	2
40	4
41	5
42	7
43	6
44	9
45	7
46	7
47	5
48	4
49	1
50	1
51	2
52	0
53	0
54	0
55	0
56	0
57	2
58	2
59	2
60	2
61	4
62	4
63	8
64	6
65	10
66	12
67	14
68	12
69	14
70	10
71	10
72	6
73	4
74	2
75	2

[1, 2, 2, 1, 1, 2, 0, 2, 2, 2, 2, 0, 0, 2, 3, 3, 4, 1, 1, 2, 0, 0, 0, 2, 2, 4, 4, 6, 4, 4, 2, 2, 2, 0, 0, 0, 0, 2, 2, 2, 4, 5, 7, 6, 9, 7, 7, 5, 4, 1, 1, 2, 0, 0, 0, 0, 0, 2, 2, 2, 2, 4, 4, 8, 6, 10, 12, 14, 12, 14, 10, 10, 6, 4, 2, 2]

cp's OEIS Frontend

A381899 Irregular triangular array read by rows. T(n,k) is the number of length n words x on {0,1} such that I(x) + W(x)*(n-W(x)) = k, where I(x) is the number of inversions in x and W(x) is the number of 1's in x, n >= 0, 0 <= k <= floor(n^2/2).

Table of values

List of values

n	a(n)
0	1
1	2
2	2
3	1
4	1
5	2
6	0
7	2
8	2
9	2
10	2
11	0
12	0
13	2
14	3
15	3
16	4
17	1
18	1
19	2
20	0
21	0
22	0
23	2
24	2
25	4
26	4
27	6
28	4
29	4
30	2
31	2
32	2
33	0
34	0
35	0
36	0
37	2
38	2
39	2
40	4
41	5
42	7
43	6
44	9
45	7
46	7
47	5
48	4
49	1
50	1
51	2
52	0
53	0
54	0
55	0
56	0
57	2
58	2
59	2
60	2
61	4
62	4
63	8
64	6
65	10
66	12
67	14
68	12
69	14
70	10
71	10
72	6
73	4
74	2
75	2

n	a(n)
0	1
1	2
2	2
3	1
4	1
5	2
6	0
7	2
8	2
9	2
10	2
11	0
12	0
13	2
14	3
15	3
16	4
17	1
18	1
19	2
20	0
21	0
22	0
23	2
24	2
25	4
26	4
27	6
28	4
29	4
30	2
31	2
32	2
33	0
34	0
35	0
36	0
37	2
38	2
39	2
40	4
41	5
42	7
43	6
44	9
45	7
46	7
47	5
48	4
49	1
50	1
51	2
52	0
53	0
54	0
55	0
56	0
57	2
58	2
59	2
60	2
61	4
62	4
63	8
64	6
65	10
66	12
67	14
68	12
69	14
70	10
71	10
72	6
73	4
74	2
75	2

n	a(n)
0	1
1	2
2	2
3	1
4	1
5	2
6	0
7	2
8	2
9	2
10	2
11	0
12	0
13	2
14	3
15	3
16	4
17	1
18	1
19	2
20	0
21	0
22	0
23	2
24	2
25	4
26	4
27	6
28	4
29	4
30	2
31	2
32	2
33	0
34	0
35	0
36	0
37	2
38	2
39	2
40	4
41	5
42	7
43	6
44	9
45	7
46	7
47	5
48	4
49	1
50	1
51	2
52	0
53	0
54	0
55	0
56	0
57	2
58	2
59	2
60	2
61	4
62	4
63	8
64	6
65	10
66	12
67	14
68	12
69	14
70	10
71	10
72	6
73	4
74	2
75	2