A384450 - cp's OEIS frontend

A384450 a(1) = 0; thereafter, a(n) is the number of arithmetic progressions of length 3 or greater at indices in an arithmetic progression ending at a(n-1).

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

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

cp's OEIS Frontend

A384450 a(1) = 0; thereafter, a(n) is the number of arithmetic progressions of length 3 or greater at indices in an arithmetic progression ending at a(n-1).

Table of values

List of values

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

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

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