A006218 - cp's OEIS frontend

A006218 a(n) = Sum_{k=1..n} floor(n/k); also Sum_{k=1..n} d(k), where d = number of divisors (A000005); also number of solutions to x*y = z with 1 <= x,y,z <= n.

n	a(n)
0	0
1	1
2	3
3	5
4	8
5	10
6	14
7	16
8	20
9	23
10	27
11	29
12	35
13	37
14	41
15	45
16	50
17	52
18	58
19	60
20	66
21	70
22	74
23	76
24	84
25	87
26	91
27	95
28	101
29	103
30	111
31	113
32	119
33	123
34	127
35	131
36	140
37	142
38	146
39	150
40	158
41	160
42	168
43	170
44	176
45	182
46	186
47	188
48	198
49	201
50	207
51	211
52	217
53	219
54	227
55	231
56	239
57	243
58	247
59	249

[0, 1, 3, 5, 8, 10, 14, 16, 20, 23, 27, 29, 35, 37, 41, 45, 50, 52, 58, 60, 66, 70, 74, 76, 84, 87, 91, 95, 101, 103, 111, 113, 119, 123, 127, 131, 140, 142, 146, 150, 158, 160, 168, 170, 176, 182, 186, 188, 198, 201, 207, 211, 217, 219, 227, 231, 239, 243, 247, 249]

cp's OEIS Frontend

A006218 a(n) = Sum_{k=1..n} floor(n/k); also Sum_{k=1..n} d(k), where d = number of divisors (A000005); also number of solutions to x*y = z with 1 <= x,y,z <= n.

Table of values

List of values

n	a(n)
0	0
1	1
2	3
3	5
4	8
5	10
6	14
7	16
8	20
9	23
10	27
11	29
12	35
13	37
14	41
15	45
16	50
17	52
18	58
19	60
20	66
21	70
22	74
23	76
24	84
25	87
26	91
27	95
28	101
29	103
30	111
31	113
32	119
33	123
34	127
35	131
36	140
37	142
38	146
39	150
40	158
41	160
42	168
43	170
44	176
45	182
46	186
47	188
48	198
49	201
50	207
51	211
52	217
53	219
54	227
55	231
56	239
57	243
58	247
59	249

n	a(n)
0	0
1	1
2	3
3	5
4	8
5	10
6	14
7	16
8	20
9	23
10	27
11	29
12	35
13	37
14	41
15	45
16	50
17	52
18	58
19	60
20	66
21	70
22	74
23	76
24	84
25	87
26	91
27	95
28	101
29	103
30	111
31	113
32	119
33	123
34	127
35	131
36	140
37	142
38	146
39	150
40	158
41	160
42	168
43	170
44	176
45	182
46	186
47	188
48	198
49	201
50	207
51	211
52	217
53	219
54	227
55	231
56	239
57	243
58	247
59	249

n	a(n)
0	0
1	1
2	3
3	5
4	8
5	10
6	14
7	16
8	20
9	23
10	27
11	29
12	35
13	37
14	41
15	45
16	50
17	52
18	58
19	60
20	66
21	70
22	74
23	76
24	84
25	87
26	91
27	95
28	101
29	103
30	111
31	113
32	119
33	123
34	127
35	131
36	140
37	142
38	146
39	150
40	158
41	160
42	168
43	170
44	176
45	182
46	186
47	188
48	198
49	201
50	207
51	211
52	217
53	219
54	227
55	231
56	239
57	243
58	247
59	249