A322982 - cp's OEIS frontend

A322982 If n is a noncomposite, then a(n) = 2*n - 1, otherwise a(n) = A032742(n), the largest proper divisor of n.

n	a(n)
1	1
2	3
3	5
4	2
5	9
6	3
7	13
8	4
9	3
10	5
11	21
12	6
13	25
14	7
15	5
16	8
17	33
18	9
19	37
20	10
21	7
22	11
23	45
24	12
25	5
26	13
27	9
28	14
29	57
30	15
31	61
32	16
33	11
34	17
35	7
36	18
37	73
38	19
39	13
40	20
41	81
42	21
43	85
44	22
45	15
46	23
47	93
48	24
49	7
50	25
51	17
52	26
53	105
54	27
55	11
56	28
57	19
58	29
59	117
60	30
61	121
62	31
63	21
64	32
65	13
66	33
67	133
68	34
69	23
70	35
71	141
72	36
73	145
74	37
75	25
76	38
77	11
78	39
79	157
80	40
81	27
82	41
83	165
84	42
85	17
86	43
87	29

[1, 3, 5, 2, 9, 3, 13, 4, 3, 5, 21, 6, 25, 7, 5, 8, 33, 9, 37, 10, 7, 11, 45, 12, 5, 13, 9, 14, 57, 15, 61, 16, 11, 17, 7, 18, 73, 19, 13, 20, 81, 21, 85, 22, 15, 23, 93, 24, 7, 25, 17, 26, 105, 27, 11, 28, 19, 29, 117, 30, 121, 31, 21, 32, 13, 33, 133, 34, 23, 35, 141, 36, 145, 37, 25, 38, 11, 39, 157, 40, 27, 41, 165, 42, 17, 43, 29]

cp's OEIS Frontend

A322982 If n is a noncomposite, then a(n) = 2*n - 1, otherwise a(n) = A032742(n), the largest proper divisor of n.

Table of values

List of values

n	a(n)
1	1
2	3
3	5
4	2
5	9
6	3
7	13
8	4
9	3
10	5
11	21
12	6
13	25
14	7
15	5
16	8
17	33
18	9
19	37
20	10
21	7
22	11
23	45
24	12
25	5
26	13
27	9
28	14
29	57
30	15
31	61
32	16
33	11
34	17
35	7
36	18
37	73
38	19
39	13
40	20
41	81
42	21
43	85
44	22
45	15
46	23
47	93
48	24
49	7
50	25
51	17
52	26
53	105
54	27
55	11
56	28
57	19
58	29
59	117
60	30
61	121
62	31
63	21
64	32
65	13
66	33
67	133
68	34
69	23
70	35
71	141
72	36
73	145
74	37
75	25
76	38
77	11
78	39
79	157
80	40
81	27
82	41
83	165
84	42
85	17
86	43
87	29

n	a(n)
1	1
2	3
3	5
4	2
5	9
6	3
7	13
8	4
9	3
10	5
11	21
12	6
13	25
14	7
15	5
16	8
17	33
18	9
19	37
20	10
21	7
22	11
23	45
24	12
25	5
26	13
27	9
28	14
29	57
30	15
31	61
32	16
33	11
34	17
35	7
36	18
37	73
38	19
39	13
40	20
41	81
42	21
43	85
44	22
45	15
46	23
47	93
48	24
49	7
50	25
51	17
52	26
53	105
54	27
55	11
56	28
57	19
58	29
59	117
60	30
61	121
62	31
63	21
64	32
65	13
66	33
67	133
68	34
69	23
70	35
71	141
72	36
73	145
74	37
75	25
76	38
77	11
78	39
79	157
80	40
81	27
82	41
83	165
84	42
85	17
86	43
87	29

n	a(n)
1	1
2	3
3	5
4	2
5	9
6	3
7	13
8	4
9	3
10	5
11	21
12	6
13	25
14	7
15	5
16	8
17	33
18	9
19	37
20	10
21	7
22	11
23	45
24	12
25	5
26	13
27	9
28	14
29	57
30	15
31	61
32	16
33	11
34	17
35	7
36	18
37	73
38	19
39	13
40	20
41	81
42	21
43	85
44	22
45	15
46	23
47	93
48	24
49	7
50	25
51	17
52	26
53	105
54	27
55	11
56	28
57	19
58	29
59	117
60	30
61	121
62	31
63	21
64	32
65	13
66	33
67	133
68	34
69	23
70	35
71	141
72	36
73	145
74	37
75	25
76	38
77	11
78	39
79	157
80	40
81	27
82	41
83	165
84	42
85	17
86	43
87	29