A109451 - cp's OEIS frontend

A109451 a(1)=1; a(n) = smallest positive integer not already present such that a(n-1) and a(n) have a different number of 1's in their binary expansions.

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

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

cp's OEIS Frontend

A109451 a(1)=1; a(n) = smallest positive integer not already present such that a(n-1) and a(n) have a different number of 1's in their binary expansions.

Table of values

List of values

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

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

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