A318789 - cp's OEIS frontend

A318789 For n >= 3, a(n) is equal to n-1 plus the alternating sum of all consecutive prime gaps between odd primes <= n.

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

[2, 3, 2, 3, 6, 7, 8, 9, 6, 7, 10, 11, 12, 13, 10, 11, 14, 15, 16, 17, 14, 15, 16, 17, 18, 19, 26, 27, 26, 27, 28, 29, 30, 31, 38, 39, 40, 41, 38, 39, 42, 43, 44, 45, 42, 43, 44, 45, 46, 47, 54, 55, 56, 57, 58, 59, 54, 55, 58, 59, 60, 61, 62, 63, 58, 59, 60, 61, 66, 67, 66, 67, 68]

cp's OEIS Frontend

A318789 For n >= 3, a(n) is equal to n-1 plus the alternating sum of all consecutive prime gaps between odd primes <= n.

Table of values

List of values

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

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

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