A156351 - cp's OEIS frontend

A156351 a(n) = Sum_{k=1..n} (-1)^K(k+1)*(K(k+1)-K(k)) where K(k) = A000002(k).

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

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

cp's OEIS Frontend

A156351 a(n) = Sum_{k=1..n} (-1)^K(k+1)*(K(k+1)-K(k)) where K(k) = A000002(k).

Table of values

List of values

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

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

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