A247243 - cp's OEIS frontend

A247243 a(n) = smallest positive integer k not already in the sequence such that the decimal expansion of 2^(n-1) begins with k.

n	a(n)
1	1
2	2
3	4
4	8
5	16
6	3
7	6
8	12
9	25
10	5
11	10
12	20
13	40
14	81
15	163
16	32
17	65
18	13
19	26
20	52
21	104
22	209
23	41
24	83
25	167
26	33
27	67
28	134
29	268
30	53
31	107
32	21
33	42
34	85
35	17
36	34
37	68
38	137
39	27
40	54
41	109
42	219
43	43
44	87
45	175
46	35
47	7
48	14
49	28
50	56
51	11
52	22
53	45
54	9
55	18
56	36
57	72
58	144
59	288
60	57
61	115
62	23
63	46
64	92

[1, 2, 4, 8, 16, 3, 6, 12, 25, 5, 10, 20, 40, 81, 163, 32, 65, 13, 26, 52, 104, 209, 41, 83, 167, 33, 67, 134, 268, 53, 107, 21, 42, 85, 17, 34, 68, 137, 27, 54, 109, 219, 43, 87, 175, 35, 7, 14, 28, 56, 11, 22, 45, 9, 18, 36, 72, 144, 288, 57, 115, 23, 46, 92]

cp's OEIS Frontend

A247243 a(n) = smallest positive integer k not already in the sequence such that the decimal expansion of 2^(n-1) begins with k.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	8
5	16
6	3
7	6
8	12
9	25
10	5
11	10
12	20
13	40
14	81
15	163
16	32
17	65
18	13
19	26
20	52
21	104
22	209
23	41
24	83
25	167
26	33
27	67
28	134
29	268
30	53
31	107
32	21
33	42
34	85
35	17
36	34
37	68
38	137
39	27
40	54
41	109
42	219
43	43
44	87
45	175
46	35
47	7
48	14
49	28
50	56
51	11
52	22
53	45
54	9
55	18
56	36
57	72
58	144
59	288
60	57
61	115
62	23
63	46
64	92

n	a(n)
1	1
2	2
3	4
4	8
5	16
6	3
7	6
8	12
9	25
10	5
11	10
12	20
13	40
14	81
15	163
16	32
17	65
18	13
19	26
20	52
21	104
22	209
23	41
24	83
25	167
26	33
27	67
28	134
29	268
30	53
31	107
32	21
33	42
34	85
35	17
36	34
37	68
38	137
39	27
40	54
41	109
42	219
43	43
44	87
45	175
46	35
47	7
48	14
49	28
50	56
51	11
52	22
53	45
54	9
55	18
56	36
57	72
58	144
59	288
60	57
61	115
62	23
63	46
64	92

n	a(n)
1	1
2	2
3	4
4	8
5	16
6	3
7	6
8	12
9	25
10	5
11	10
12	20
13	40
14	81
15	163
16	32
17	65
18	13
19	26
20	52
21	104
22	209
23	41
24	83
25	167
26	33
27	67
28	134
29	268
30	53
31	107
32	21
33	42
34	85
35	17
36	34
37	68
38	137
39	27
40	54
41	109
42	219
43	43
44	87
45	175
46	35
47	7
48	14
49	28
50	56
51	11
52	22
53	45
54	9
55	18
56	36
57	72
58	144
59	288
60	57
61	115
62	23
63	46
64	92