A325970 - cp's OEIS frontend

A325970 a(n) is the largest k <= A066503(n) such that k and (2n-sigma(n)) [= A033879(n)] are relatively prime.

n	a(n)
1	0
2	0
3	-1
4	2
5	-1
6	-1
7	-1
8	6
9	6
10	-1
11	-1
12	5
13	-1
14	-1
15	-1
16	14
17	-1
18	11
19	-1
20	9
21	-1
22	-1
23	-1
24	17
25	20
26	-1
27	23
28	1
29	-1
30	-1
31	-1
32	30
33	-1
34	-1
35	-1
36	30
37	-1
38	-1
39	-1
40	29
41	-1
42	-1
43	-1
44	21
45	29
46	-1
47	-1
48	41
49	42
50	40
51	-1
52	25
53	-1
54	47
55	-1
56	41
57	-1
58	-1
59	-1
60	29
61	-1
62	-1
63	41
64	62
65	-1
66	-1
67	-1
68	33
69	-1
70	-1
71	-1
72	65
73	-1
74	-1
75	59
76	37
77	-1
78	-1
79	-1
80	69
81	78

[0, 0, -1, 2, -1, -1, -1, 6, 6, -1, -1, 5, -1, -1, -1, 14, -1, 11, -1, 9, -1, -1, -1, 17, 20, -1, 23, 1, -1, -1, -1, 30, -1, -1, -1, 30, -1, -1, -1, 29, -1, -1, -1, 21, 29, -1, -1, 41, 42, 40, -1, 25, -1, 47, -1, 41, -1, -1, -1, 29, -1, -1, 41, 62, -1, -1, -1, 33, -1, -1, -1, 65, -1, -1, 59, 37, -1, -1, -1, 69, 78]

cp's OEIS Frontend

A325970 a(n) is the largest k <= A066503(n) such that k and (2n-sigma(n)) [= A033879(n)] are relatively prime.

Table of values

List of values

n	a(n)
1	0
2	0
3	-1
4	2
5	-1
6	-1
7	-1
8	6
9	6
10	-1
11	-1
12	5
13	-1
14	-1
15	-1
16	14
17	-1
18	11
19	-1
20	9
21	-1
22	-1
23	-1
24	17
25	20
26	-1
27	23
28	1
29	-1
30	-1
31	-1
32	30
33	-1
34	-1
35	-1
36	30
37	-1
38	-1
39	-1
40	29
41	-1
42	-1
43	-1
44	21
45	29
46	-1
47	-1
48	41
49	42
50	40
51	-1
52	25
53	-1
54	47
55	-1
56	41
57	-1
58	-1
59	-1
60	29
61	-1
62	-1
63	41
64	62
65	-1
66	-1
67	-1
68	33
69	-1
70	-1
71	-1
72	65
73	-1
74	-1
75	59
76	37
77	-1
78	-1
79	-1
80	69
81	78

n	a(n)
1	0
2	0
3	-1
4	2
5	-1
6	-1
7	-1
8	6
9	6
10	-1
11	-1
12	5
13	-1
14	-1
15	-1
16	14
17	-1
18	11
19	-1
20	9
21	-1
22	-1
23	-1
24	17
25	20
26	-1
27	23
28	1
29	-1
30	-1
31	-1
32	30
33	-1
34	-1
35	-1
36	30
37	-1
38	-1
39	-1
40	29
41	-1
42	-1
43	-1
44	21
45	29
46	-1
47	-1
48	41
49	42
50	40
51	-1
52	25
53	-1
54	47
55	-1
56	41
57	-1
58	-1
59	-1
60	29
61	-1
62	-1
63	41
64	62
65	-1
66	-1
67	-1
68	33
69	-1
70	-1
71	-1
72	65
73	-1
74	-1
75	59
76	37
77	-1
78	-1
79	-1
80	69
81	78

n	a(n)
1	0
2	0
3	-1
4	2
5	-1
6	-1
7	-1
8	6
9	6
10	-1
11	-1
12	5
13	-1
14	-1
15	-1
16	14
17	-1
18	11
19	-1
20	9
21	-1
22	-1
23	-1
24	17
25	20
26	-1
27	23
28	1
29	-1
30	-1
31	-1
32	30
33	-1
34	-1
35	-1
36	30
37	-1
38	-1
39	-1
40	29
41	-1
42	-1
43	-1
44	21
45	29
46	-1
47	-1
48	41
49	42
50	40
51	-1
52	25
53	-1
54	47
55	-1
56	41
57	-1
58	-1
59	-1
60	29
61	-1
62	-1
63	41
64	62
65	-1
66	-1
67	-1
68	33
69	-1
70	-1
71	-1
72	65
73	-1
74	-1
75	59
76	37
77	-1
78	-1
79	-1
80	69
81	78