A330560 - cp's OEIS frontend

A330560 a(n) = number of primes p <= prime(n) with Delta(p) == 2 (mod 4), where Delta(p) = nextprime(p) - p.

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

[0, 1, 2, 2, 3, 3, 4, 4, 5, 6, 7, 7, 8, 8, 9, 10, 11, 12, 12, 13, 14, 14, 15, 15, 15, 16, 16, 17, 17, 18, 18, 19, 20, 21, 22, 23, 24, 24, 25, 26, 27, 28, 29, 29, 30, 30, 30, 30, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 39, 40, 41, 42, 42, 43, 43, 44, 45, 46, 47, 47, 48, 48, 49, 50, 50, 51, 51, 51, 51, 52, 53, 54]

cp's OEIS Frontend

A330560 a(n) = number of primes p <= prime(n) with Delta(p) == 2 (mod 4), where Delta(p) = nextprime(p) - p.

Table of values

List of values

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

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

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