A024870 - cp's OEIS frontend

A024870 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = A023531.

n	a(n)
2	2
3	0
4	0
5	2
6	3
7	4
8	5
9	2
10	3
11	4
12	5
13	6
14	9
15	11
16	13
17	5
18	6
19	7
20	10
21	12
22	14
23	16
24	18
25	20
26	22
27	11
28	13
29	15
30	17
31	19
32	21
33	23
34	25
35	29
36	32
37	35
38	38
39	20
40	22
41	24
42	26
43	28
44	32
45	35
46	38
47	41
48	44
49	47
50	50
51	53
52	56
53	31
54	35
55	38
56	41
57	44
58	47
59	50
60	53
61	56
62	59
63	62
64	65
65	70
66	74
67	78
68	82
69	50
70	53
71	56
72	59
73	62
74	65
75	68
76	71
77	76
78	80
79	84
80	88

[2, 0, 0, 2, 3, 4, 5, 2, 3, 4, 5, 6, 9, 11, 13, 5, 6, 7, 10, 12, 14, 16, 18, 20, 22, 11, 13, 15, 17, 19, 21, 23, 25, 29, 32, 35, 38, 20, 22, 24, 26, 28, 32, 35, 38, 41, 44, 47, 50, 53, 56, 31, 35, 38, 41, 44, 47, 50, 53, 56, 59, 62, 65, 70, 74, 78, 82, 50, 53, 56, 59, 62, 65, 68, 71, 76, 80, 84, 88]

cp's OEIS Frontend

A024870 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = A023531.

Table of values

List of values

n	a(n)
2	2
3	0
4	0
5	2
6	3
7	4
8	5
9	2
10	3
11	4
12	5
13	6
14	9
15	11
16	13
17	5
18	6
19	7
20	10
21	12
22	14
23	16
24	18
25	20
26	22
27	11
28	13
29	15
30	17
31	19
32	21
33	23
34	25
35	29
36	32
37	35
38	38
39	20
40	22
41	24
42	26
43	28
44	32
45	35
46	38
47	41
48	44
49	47
50	50
51	53
52	56
53	31
54	35
55	38
56	41
57	44
58	47
59	50
60	53
61	56
62	59
63	62
64	65
65	70
66	74
67	78
68	82
69	50
70	53
71	56
72	59
73	62
74	65
75	68
76	71
77	76
78	80
79	84
80	88

n	a(n)
2	2
3	0
4	0
5	2
6	3
7	4
8	5
9	2
10	3
11	4
12	5
13	6
14	9
15	11
16	13
17	5
18	6
19	7
20	10
21	12
22	14
23	16
24	18
25	20
26	22
27	11
28	13
29	15
30	17
31	19
32	21
33	23
34	25
35	29
36	32
37	35
38	38
39	20
40	22
41	24
42	26
43	28
44	32
45	35
46	38
47	41
48	44
49	47
50	50
51	53
52	56
53	31
54	35
55	38
56	41
57	44
58	47
59	50
60	53
61	56
62	59
63	62
64	65
65	70
66	74
67	78
68	82
69	50
70	53
71	56
72	59
73	62
74	65
75	68
76	71
77	76
78	80
79	84
80	88

n	a(n)
2	2
3	0
4	0
5	2
6	3
7	4
8	5
9	2
10	3
11	4
12	5
13	6
14	9
15	11
16	13
17	5
18	6
19	7
20	10
21	12
22	14
23	16
24	18
25	20
26	22
27	11
28	13
29	15
30	17
31	19
32	21
33	23
34	25
35	29
36	32
37	35
38	38
39	20
40	22
41	24
42	26
43	28
44	32
45	35
46	38
47	41
48	44
49	47
50	50
51	53
52	56
53	31
54	35
55	38
56	41
57	44
58	47
59	50
60	53
61	56
62	59
63	62
64	65
65	70
66	74
67	78
68	82
69	50
70	53
71	56
72	59
73	62
74	65
75	68
76	71
77	76
78	80
79	84
80	88