A325976 - cp's OEIS frontend

A325976 a(n) is the largest k <= n such that k and (2n-sigma(n)) [= A033879(n)] are relatively prime.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	1
7	7
8	8
9	9
10	9
11	11
12	11
13	13
14	13
15	13
16	16
17	17
18	17
19	19
20	19
21	21
22	21
23	23
24	23
25	25
26	23
27	27
28	1
29	29
30	29
31	31
32	32
33	31
34	33
35	35
36	36
37	37
38	37
39	39
40	39
41	41
42	41
43	43
44	43
45	43
46	43
47	47
48	47
49	49
50	50
51	49
52	49
53	53
54	53
55	55
56	55
57	57
58	57
59	59
60	59
61	61
62	61
63	63
64	64
65	65
66	65
67	67
68	67
69	67
70	69
71	71
72	71
73	73
74	73
75	75
76	73
77	77
78	77
79	79
80	79
81	81
82	81
83	83
84	83
85	85
86	83

[1, 2, 3, 4, 5, 1, 7, 8, 9, 9, 11, 11, 13, 13, 13, 16, 17, 17, 19, 19, 21, 21, 23, 23, 25, 23, 27, 1, 29, 29, 31, 32, 31, 33, 35, 36, 37, 37, 39, 39, 41, 41, 43, 43, 43, 43, 47, 47, 49, 50, 49, 49, 53, 53, 55, 55, 57, 57, 59, 59, 61, 61, 63, 64, 65, 65, 67, 67, 67, 69, 71, 71, 73, 73, 75, 73, 77, 77, 79, 79, 81, 81, 83, 83, 85, 83]

cp's OEIS Frontend

A325976 a(n) is the largest k <= n such that k and (2n-sigma(n)) [= A033879(n)] are relatively prime.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	1
7	7
8	8
9	9
10	9
11	11
12	11
13	13
14	13
15	13
16	16
17	17
18	17
19	19
20	19
21	21
22	21
23	23
24	23
25	25
26	23
27	27
28	1
29	29
30	29
31	31
32	32
33	31
34	33
35	35
36	36
37	37
38	37
39	39
40	39
41	41
42	41
43	43
44	43
45	43
46	43
47	47
48	47
49	49
50	50
51	49
52	49
53	53
54	53
55	55
56	55
57	57
58	57
59	59
60	59
61	61
62	61
63	63
64	64
65	65
66	65
67	67
68	67
69	67
70	69
71	71
72	71
73	73
74	73
75	75
76	73
77	77
78	77
79	79
80	79
81	81
82	81
83	83
84	83
85	85
86	83

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	1
7	7
8	8
9	9
10	9
11	11
12	11
13	13
14	13
15	13
16	16
17	17
18	17
19	19
20	19
21	21
22	21
23	23
24	23
25	25
26	23
27	27
28	1
29	29
30	29
31	31
32	32
33	31
34	33
35	35
36	36
37	37
38	37
39	39
40	39
41	41
42	41
43	43
44	43
45	43
46	43
47	47
48	47
49	49
50	50
51	49
52	49
53	53
54	53
55	55
56	55
57	57
58	57
59	59
60	59
61	61
62	61
63	63
64	64
65	65
66	65
67	67
68	67
69	67
70	69
71	71
72	71
73	73
74	73
75	75
76	73
77	77
78	77
79	79
80	79
81	81
82	81
83	83
84	83
85	85
86	83

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	1
7	7
8	8
9	9
10	9
11	11
12	11
13	13
14	13
15	13
16	16
17	17
18	17
19	19
20	19
21	21
22	21
23	23
24	23
25	25
26	23
27	27
28	1
29	29
30	29
31	31
32	32
33	31
34	33
35	35
36	36
37	37
38	37
39	39
40	39
41	41
42	41
43	43
44	43
45	43
46	43
47	47
48	47
49	49
50	50
51	49
52	49
53	53
54	53
55	55
56	55
57	57
58	57
59	59
60	59
61	61
62	61
63	63
64	64
65	65
66	65
67	67
68	67
69	67
70	69
71	71
72	71
73	73
74	73
75	75
76	73
77	77
78	77
79	79
80	79
81	81
82	81
83	83
84	83
85	85
86	83