A358208 - cp's OEIS frontend

A358208 a(1) = 1; a(2) = 2; a(3) = 3; for n > 3, a(n) is the smallest positive number not occurring earlier that shares a factor with Sum_{k=1..n-1} A001065(k), where A001065(k) is the sum of the proper divisors of k.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	8
8	13
9	10
10	9
11	12
12	11
13	7
14	14
15	15
16	18
17	16
18	17
19	20
20	107
21	21
22	22
23	24
24	25
25	191
26	197
27	27
28	26
29	28
30	30
31	33
32	32
33	35
34	34
35	36
36	29
37	38
38	433
39	39
40	40
41	42
42	523
43	577
44	44
45	45
46	31
47	677
48	46
49	48
50	50
51	23
52	49
53	52
54	51
55	54
56	56
57	55
58	63
59	43
60	58
61	37
62	57
63	53
64	60
65	66
66	61
67	62
68	70
69	68
70	64
71	65
72	69
73	71
74	75
75	80

[1, 2, 3, 4, 5, 6, 8, 13, 10, 9, 12, 11, 7, 14, 15, 18, 16, 17, 20, 107, 21, 22, 24, 25, 191, 197, 27, 26, 28, 30, 33, 32, 35, 34, 36, 29, 38, 433, 39, 40, 42, 523, 577, 44, 45, 31, 677, 46, 48, 50, 23, 49, 52, 51, 54, 56, 55, 63, 43, 58, 37, 57, 53, 60, 66, 61, 62, 70, 68, 64, 65, 69, 71, 75, 80]

cp's OEIS Frontend

A358208 a(1) = 1; a(2) = 2; a(3) = 3; for n > 3, a(n) is the smallest positive number not occurring earlier that shares a factor with Sum_{k=1..n-1} A001065(k), where A001065(k) is the sum of the proper divisors of k.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	8
8	13
9	10
10	9
11	12
12	11
13	7
14	14
15	15
16	18
17	16
18	17
19	20
20	107
21	21
22	22
23	24
24	25
25	191
26	197
27	27
28	26
29	28
30	30
31	33
32	32
33	35
34	34
35	36
36	29
37	38
38	433
39	39
40	40
41	42
42	523
43	577
44	44
45	45
46	31
47	677
48	46
49	48
50	50
51	23
52	49
53	52
54	51
55	54
56	56
57	55
58	63
59	43
60	58
61	37
62	57
63	53
64	60
65	66
66	61
67	62
68	70
69	68
70	64
71	65
72	69
73	71
74	75
75	80

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	8
8	13
9	10
10	9
11	12
12	11
13	7
14	14
15	15
16	18
17	16
18	17
19	20
20	107
21	21
22	22
23	24
24	25
25	191
26	197
27	27
28	26
29	28
30	30
31	33
32	32
33	35
34	34
35	36
36	29
37	38
38	433
39	39
40	40
41	42
42	523
43	577
44	44
45	45
46	31
47	677
48	46
49	48
50	50
51	23
52	49
53	52
54	51
55	54
56	56
57	55
58	63
59	43
60	58
61	37
62	57
63	53
64	60
65	66
66	61
67	62
68	70
69	68
70	64
71	65
72	69
73	71
74	75
75	80

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	8
8	13
9	10
10	9
11	12
12	11
13	7
14	14
15	15
16	18
17	16
18	17
19	20
20	107
21	21
22	22
23	24
24	25
25	191
26	197
27	27
28	26
29	28
30	30
31	33
32	32
33	35
34	34
35	36
36	29
37	38
38	433
39	39
40	40
41	42
42	523
43	577
44	44
45	45
46	31
47	677
48	46
49	48
50	50
51	23
52	49
53	52
54	51
55	54
56	56
57	55
58	63
59	43
60	58
61	37
62	57
63	53
64	60
65	66
66	61
67	62
68	70
69	68
70	64
71	65
72	69
73	71
74	75
75	80