A330559 - cp's OEIS frontend

A330559 a(n) = (number of primes p <= prime(n) with Delta(p) == 2 (mod 4)) - (number of primes p <= prime(n) with Delta(p) == 0 (mod 4)), where Delta(p) = nextprime(p) - p.

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

[0, 1, 2, 1, 2, 1, 2, 1, 2, 3, 4, 3, 4, 3, 4, 5, 6, 7, 6, 7, 8, 7, 8, 7, 6, 7, 6, 7, 6, 7, 6, 7, 8, 9, 10, 11, 12, 11, 12, 13, 14, 15, 16, 15, 16, 15, 14, 13, 14, 13, 14, 15, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 22, 23, 22, 23, 24, 25, 26, 25, 26, 25, 26, 27, 26, 27, 26, 25, 24, 25, 26, 27, 28, 29, 28]

cp's OEIS Frontend

A330559 a(n) = (number of primes p <= prime(n) with Delta(p) == 2 (mod 4)) - (number of primes p <= prime(n) with Delta(p) == 0 (mod 4)), where Delta(p) = nextprime(p) - p.

Table of values

List of values

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

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

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