A323161 - cp's OEIS frontend

A323161 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n<=3) = -n, f(n) = 0 if n-1 is an odd prime, and f(n) = floor((n-1)/2) for all other numbers.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	4
7	6
8	4
9	7
10	7
11	8
12	4
13	9
14	4
15	10
16	10
17	11
18	4
19	12
20	4
21	13
22	13
23	14
24	4
25	15
26	15
27	16
28	16
29	17
30	4
31	18
32	4
33	19
34	19
35	20
36	20
37	21
38	4
39	22
40	22
41	23
42	4
43	24
44	4
45	25
46	25
47	26
48	4
49	27
50	27
51	28
52	28
53	29
54	4
55	30
56	30
57	31
58	31
59	32
60	4
61	33
62	4
63	34
64	34
65	35
66	35
67	36
68	4
69	37
70	37
71	38
72	4
73	39
74	4
75	40
76	40
77	41
78	41
79	42
80	4
81	43
82	43
83	44
84	4
85	45
86	45
87	46
88	46
89	47
90	4
91	48
92	48
93	49
94	49
95	50
96	50
97	51
98	4
99	52
100	52
101	53
102	4
103	54
104	4

[1, 2, 3, 4, 5, 4, 6, 4, 7, 7, 8, 4, 9, 4, 10, 10, 11, 4, 12, 4, 13, 13, 14, 4, 15, 15, 16, 16, 17, 4, 18, 4, 19, 19, 20, 20, 21, 4, 22, 22, 23, 4, 24, 4, 25, 25, 26, 4, 27, 27, 28, 28, 29, 4, 30, 30, 31, 31, 32, 4, 33, 4, 34, 34, 35, 35, 36, 4, 37, 37, 38, 4, 39, 4, 40, 40, 41, 41, 42, 4, 43, 43, 44, 4, 45, 45, 46, 46, 47, 4, 48, 48, 49, 49, 50, 50, 51, 4, 52, 52, 53, 4, 54, 4]

cp's OEIS Frontend

A323161 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n<=3) = -n, f(n) = 0 if n-1 is an odd prime, and f(n) = floor((n-1)/2) for all other numbers.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	4
7	6
8	4
9	7
10	7
11	8
12	4
13	9
14	4
15	10
16	10
17	11
18	4
19	12
20	4
21	13
22	13
23	14
24	4
25	15
26	15
27	16
28	16
29	17
30	4
31	18
32	4
33	19
34	19
35	20
36	20
37	21
38	4
39	22
40	22
41	23
42	4
43	24
44	4
45	25
46	25
47	26
48	4
49	27
50	27
51	28
52	28
53	29
54	4
55	30
56	30
57	31
58	31
59	32
60	4
61	33
62	4
63	34
64	34
65	35
66	35
67	36
68	4
69	37
70	37
71	38
72	4
73	39
74	4
75	40
76	40
77	41
78	41
79	42
80	4
81	43
82	43
83	44
84	4
85	45
86	45
87	46
88	46
89	47
90	4
91	48
92	48
93	49
94	49
95	50
96	50
97	51
98	4
99	52
100	52
101	53
102	4
103	54
104	4

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	4
7	6
8	4
9	7
10	7
11	8
12	4
13	9
14	4
15	10
16	10
17	11
18	4
19	12
20	4
21	13
22	13
23	14
24	4
25	15
26	15
27	16
28	16
29	17
30	4
31	18
32	4
33	19
34	19
35	20
36	20
37	21
38	4
39	22
40	22
41	23
42	4
43	24
44	4
45	25
46	25
47	26
48	4
49	27
50	27
51	28
52	28
53	29
54	4
55	30
56	30
57	31
58	31
59	32
60	4
61	33
62	4
63	34
64	34
65	35
66	35
67	36
68	4
69	37
70	37
71	38
72	4
73	39
74	4
75	40
76	40
77	41
78	41
79	42
80	4
81	43
82	43
83	44
84	4
85	45
86	45
87	46
88	46
89	47
90	4
91	48
92	48
93	49
94	49
95	50
96	50
97	51
98	4
99	52
100	52
101	53
102	4
103	54
104	4

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	4
7	6
8	4
9	7
10	7
11	8
12	4
13	9
14	4
15	10
16	10
17	11
18	4
19	12
20	4
21	13
22	13
23	14
24	4
25	15
26	15
27	16
28	16
29	17
30	4
31	18
32	4
33	19
34	19
35	20
36	20
37	21
38	4
39	22
40	22
41	23
42	4
43	24
44	4
45	25
46	25
47	26
48	4
49	27
50	27
51	28
52	28
53	29
54	4
55	30
56	30
57	31
58	31
59	32
60	4
61	33
62	4
63	34
64	34
65	35
66	35
67	36
68	4
69	37
70	37
71	38
72	4
73	39
74	4
75	40
76	40
77	41
78	41
79	42
80	4
81	43
82	43
83	44
84	4
85	45
86	45
87	46
88	46
89	47
90	4
91	48
92	48
93	49
94	49
95	50
96	50
97	51
98	4
99	52
100	52
101	53
102	4
103	54
104	4