A140221 - cp's OEIS frontend

A140221 A number n is included if n is coprime to Sum_{k=1..n} d(k), where d(k) is the number of divisors of k.

n	a(n)
1	1
2	2
3	3
4	7
5	9
6	10
7	11
8	12
9	13
10	14
11	17
12	19
13	23
14	25
15	27
16	28
17	29
18	31
19	32
20	34
21	35
22	37
23	41
24	43
25	45
26	49
27	50
28	51
29	52
30	53
31	54
32	56
33	58
34	59
35	61
36	62
37	65
38	67
39	69
40	71
41	73
42	75
43	77
44	79
45	81
46	82
47	83
48	84
49	86
50	87
51	88
52	89
53	92
54	93
55	94
56	95
57	97
58	98
59	101
60	103
61	107
62	109
63	111
64	113
65	115
66	117
67	119
68	122

[1, 2, 3, 7, 9, 10, 11, 12, 13, 14, 17, 19, 23, 25, 27, 28, 29, 31, 32, 34, 35, 37, 41, 43, 45, 49, 50, 51, 52, 53, 54, 56, 58, 59, 61, 62, 65, 67, 69, 71, 73, 75, 77, 79, 81, 82, 83, 84, 86, 87, 88, 89, 92, 93, 94, 95, 97, 98, 101, 103, 107, 109, 111, 113, 115, 117, 119, 122]

cp's OEIS Frontend

A140221 A number n is included if n is coprime to Sum_{k=1..n} d(k), where d(k) is the number of divisors of k.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	7
5	9
6	10
7	11
8	12
9	13
10	14
11	17
12	19
13	23
14	25
15	27
16	28
17	29
18	31
19	32
20	34
21	35
22	37
23	41
24	43
25	45
26	49
27	50
28	51
29	52
30	53
31	54
32	56
33	58
34	59
35	61
36	62
37	65
38	67
39	69
40	71
41	73
42	75
43	77
44	79
45	81
46	82
47	83
48	84
49	86
50	87
51	88
52	89
53	92
54	93
55	94
56	95
57	97
58	98
59	101
60	103
61	107
62	109
63	111
64	113
65	115
66	117
67	119
68	122

n	a(n)
1	1
2	2
3	3
4	7
5	9
6	10
7	11
8	12
9	13
10	14
11	17
12	19
13	23
14	25
15	27
16	28
17	29
18	31
19	32
20	34
21	35
22	37
23	41
24	43
25	45
26	49
27	50
28	51
29	52
30	53
31	54
32	56
33	58
34	59
35	61
36	62
37	65
38	67
39	69
40	71
41	73
42	75
43	77
44	79
45	81
46	82
47	83
48	84
49	86
50	87
51	88
52	89
53	92
54	93
55	94
56	95
57	97
58	98
59	101
60	103
61	107
62	109
63	111
64	113
65	115
66	117
67	119
68	122

n	a(n)
1	1
2	2
3	3
4	7
5	9
6	10
7	11
8	12
9	13
10	14
11	17
12	19
13	23
14	25
15	27
16	28
17	29
18	31
19	32
20	34
21	35
22	37
23	41
24	43
25	45
26	49
27	50
28	51
29	52
30	53
31	54
32	56
33	58
34	59
35	61
36	62
37	65
38	67
39	69
40	71
41	73
42	75
43	77
44	79
45	81
46	82
47	83
48	84
49	86
50	87
51	88
52	89
53	92
54	93
55	94
56	95
57	97
58	98
59	101
60	103
61	107
62	109
63	111
64	113
65	115
66	117
67	119
68	122