A325818 - cp's OEIS frontend

A325818 a(n) is the largest k <= sigma(n) such that n-k and n-(sigma(n)-k) are relatively prime.

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	8
8	15
9	13
10	17
11	12
12	27
13	14
14	23
15	22
16	31
17	18
18	38
19	20
20	41
21	32
22	35
23	24
24	59
25	31
26	39
27	40
28	29
29	30
30	71
31	32
32	63
33	46
34	53
35	48
36	91
37	38
38	59
39	56
40	89
41	42
42	95
43	44
44	83
45	76
46	69
47	48
48	123
49	57
50	93
51	70
52	95
53	54
54	119
55	72
56	119
57	80
58	89
59	60
60	167
61	62
62	95
63	104
64	127
65	84
66	143
67	68
68	125
69	94
70	143
71	72
72	194
73	74
74	113
75	124
76	137
77	96

[1, 3, 4, 7, 6, 7, 8, 15, 13, 17, 12, 27, 14, 23, 22, 31, 18, 38, 20, 41, 32, 35, 24, 59, 31, 39, 40, 29, 30, 71, 32, 63, 46, 53, 48, 91, 38, 59, 56, 89, 42, 95, 44, 83, 76, 69, 48, 123, 57, 93, 70, 95, 54, 119, 72, 119, 80, 89, 60, 167, 62, 95, 104, 127, 84, 143, 68, 125, 94, 143, 72, 194, 74, 113, 124, 137, 96]

cp's OEIS Frontend

A325818 a(n) is the largest k <= sigma(n) such that n-k and n-(sigma(n)-k) are relatively prime.

Table of values

List of values

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	8
8	15
9	13
10	17
11	12
12	27
13	14
14	23
15	22
16	31
17	18
18	38
19	20
20	41
21	32
22	35
23	24
24	59
25	31
26	39
27	40
28	29
29	30
30	71
31	32
32	63
33	46
34	53
35	48
36	91
37	38
38	59
39	56
40	89
41	42
42	95
43	44
44	83
45	76
46	69
47	48
48	123
49	57
50	93
51	70
52	95
53	54
54	119
55	72
56	119
57	80
58	89
59	60
60	167
61	62
62	95
63	104
64	127
65	84
66	143
67	68
68	125
69	94
70	143
71	72
72	194
73	74
74	113
75	124
76	137
77	96

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	8
8	15
9	13
10	17
11	12
12	27
13	14
14	23
15	22
16	31
17	18
18	38
19	20
20	41
21	32
22	35
23	24
24	59
25	31
26	39
27	40
28	29
29	30
30	71
31	32
32	63
33	46
34	53
35	48
36	91
37	38
38	59
39	56
40	89
41	42
42	95
43	44
44	83
45	76
46	69
47	48
48	123
49	57
50	93
51	70
52	95
53	54
54	119
55	72
56	119
57	80
58	89
59	60
60	167
61	62
62	95
63	104
64	127
65	84
66	143
67	68
68	125
69	94
70	143
71	72
72	194
73	74
74	113
75	124
76	137
77	96

n	a(n)
1	1
2	3
3	4
4	7
5	6
6	7
7	8
8	15
9	13
10	17
11	12
12	27
13	14
14	23
15	22
16	31
17	18
18	38
19	20
20	41
21	32
22	35
23	24
24	59
25	31
26	39
27	40
28	29
29	30
30	71
31	32
32	63
33	46
34	53
35	48
36	91
37	38
38	59
39	56
40	89
41	42
42	95
43	44
44	83
45	76
46	69
47	48
48	123
49	57
50	93
51	70
52	95
53	54
54	119
55	72
56	119
57	80
58	89
59	60
60	167
61	62
62	95
63	104
64	127
65	84
66	143
67	68
68	125
69	94
70	143
71	72
72	194
73	74
74	113
75	124
76	137
77	96