A243352 - cp's OEIS frontend

A243352 If n is k-th squarefree number [i.e., n = A005117(k)], a(n) = 2k-1; otherwise, when n is k-th nonsquarefree number [i.e., n = A013929(k)], a(n) = 2k.

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

[1, 3, 5, 2, 7, 9, 11, 4, 6, 13, 15, 8, 17, 19, 21, 10, 23, 12, 25, 14, 27, 29, 31, 16, 18, 33, 20, 22, 35, 37, 39, 24, 41, 43, 45, 26, 47, 49, 51, 28, 53, 55, 57, 30, 32, 59, 61, 34, 36, 38, 63, 40, 65, 42, 67, 44, 69, 71, 73, 46, 75, 77, 48, 50, 79, 81, 83, 52, 85, 87, 89]

cp's OEIS Frontend

A243352 If n is k-th squarefree number [i.e., n = A005117(k)], a(n) = 2k-1; otherwise, when n is k-th nonsquarefree number [i.e., n = A013929(k)], a(n) = 2k.

Table of values

List of values

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

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

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