A073898 - cp's OEIS frontend

A073898 a(1) = 1; for n>1, a(n) = smallest even or odd number not occurring earlier accordingly as n is prime or composite.

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

[1, 2, 4, 3, 6, 5, 8, 7, 9, 11, 10, 13, 12, 15, 17, 19, 14, 21, 16, 23, 25, 27, 18, 29, 31, 33, 35, 37, 20, 39, 22, 41, 43, 45, 47, 49, 24, 51, 53, 55, 26, 57, 28, 59, 61, 63, 30, 65, 67, 69, 71, 73, 32, 75, 77, 79, 81, 83, 34, 85, 36, 87, 89, 91, 93, 95, 38, 97, 99, 101, 40, 103]

cp's OEIS Frontend

A073898 a(1) = 1; for n>1, a(n) = smallest even or odd number not occurring earlier accordingly as n is prime or composite.

Table of values

List of values

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

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

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