A007378 - cp's OEIS frontend

A007378 a(n), for n >= 2, is smallest positive integer which is consistent with sequence being monotonically increasing and satisfying a(a(n)) = 2n.

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

[3, 4, 6, 7, 8, 10, 12, 13, 14, 15, 16, 18, 20, 22, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 36, 38, 40, 42, 44, 46, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 97, 98, 99, 100, 101, 102, 103]

cp's OEIS Frontend

A007378 a(n), for n >= 2, is smallest positive integer which is consistent with sequence being monotonically increasing and satisfying a(a(n)) = 2n.

Table of values

List of values

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

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

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