A319706 - cp's OEIS frontend

A319706 Filter sequence which for primes p records the prime signature of 2p+1, and for all other numbers assigns a unique number.

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

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

cp's OEIS Frontend

A319706 Filter sequence which for primes p records the prime signature of 2p+1, and for all other numbers assigns a unique number.

Table of values

List of values

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

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

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