A375421 - cp's OEIS frontend

A375421 a(n) is the number of distinct straight lines passing through the points (k, prime(k)) and (n, prime(n)) for k < n (where prime(k) denotes the k-th prime number).

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

[0, 1, 2, 2, 4, 5, 5, 5, 6, 8, 9, 9, 9, 11, 10, 11, 13, 12, 16, 16, 14, 16, 16, 19, 22, 22, 21, 23, 24, 23, 28, 29, 27, 29, 30, 29, 29, 32, 31, 32, 34, 35, 35, 37, 36, 37, 39, 42, 44, 45, 45, 43, 44, 47, 47, 48, 48, 49, 46, 49, 49, 49, 56, 56, 53, 55, 61, 62]

cp's OEIS Frontend

A375421 a(n) is the number of distinct straight lines passing through the points (k, prime(k)) and (n, prime(n)) for k < n (where prime(k) denotes the k-th prime number).

Table of values

List of values

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

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

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