A270033 - cp's OEIS frontend

A270033 a(n) is the smallest b for which the base-b representation of n contains at least one 7 (or 0 if no such base exists).

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	8
8	0
9	0
10	0
11	0
12	0
13	0
14	0
15	8
16	9
17	10
18	11
19	12
20	13
21	14
22	15
23	8
24	17
25	9
26	19
27	10
28	21
29	11
30	23
31	8
32	25
33	13
34	9
35	14
36	29
37	10
38	31
39	8
40	11
41	17
42	35
43	9
44	37
45	19
46	13
47	8
48	41
49	14
50	43
51	11
52	9
53	23
54	47
55	8
56	8
57	8
58	8
59	8
60	8
61	8
62	8
63	8
64	9
65	9
66	9
67	9
68	9
69	9
70	9
71	8
72	10
73	10
74	10
75	10
76	10
77	10
78	10
79	8
80	11
81	11

[0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 8, 9, 10, 11, 12, 13, 14, 15, 8, 17, 9, 19, 10, 21, 11, 23, 8, 25, 13, 9, 14, 29, 10, 31, 8, 11, 17, 35, 9, 37, 19, 13, 8, 41, 14, 43, 11, 9, 23, 47, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 8, 10, 10, 10, 10, 10, 10, 10, 8, 11, 11]

cp's OEIS Frontend

A270033 a(n) is the smallest b for which the base-b representation of n contains at least one 7 (or 0 if no such base exists).

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	8
8	0
9	0
10	0
11	0
12	0
13	0
14	0
15	8
16	9
17	10
18	11
19	12
20	13
21	14
22	15
23	8
24	17
25	9
26	19
27	10
28	21
29	11
30	23
31	8
32	25
33	13
34	9
35	14
36	29
37	10
38	31
39	8
40	11
41	17
42	35
43	9
44	37
45	19
46	13
47	8
48	41
49	14
50	43
51	11
52	9
53	23
54	47
55	8
56	8
57	8
58	8
59	8
60	8
61	8
62	8
63	8
64	9
65	9
66	9
67	9
68	9
69	9
70	9
71	8
72	10
73	10
74	10
75	10
76	10
77	10
78	10
79	8
80	11
81	11

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	8
8	0
9	0
10	0
11	0
12	0
13	0
14	0
15	8
16	9
17	10
18	11
19	12
20	13
21	14
22	15
23	8
24	17
25	9
26	19
27	10
28	21
29	11
30	23
31	8
32	25
33	13
34	9
35	14
36	29
37	10
38	31
39	8
40	11
41	17
42	35
43	9
44	37
45	19
46	13
47	8
48	41
49	14
50	43
51	11
52	9
53	23
54	47
55	8
56	8
57	8
58	8
59	8
60	8
61	8
62	8
63	8
64	9
65	9
66	9
67	9
68	9
69	9
70	9
71	8
72	10
73	10
74	10
75	10
76	10
77	10
78	10
79	8
80	11
81	11

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	8
8	0
9	0
10	0
11	0
12	0
13	0
14	0
15	8
16	9
17	10
18	11
19	12
20	13
21	14
22	15
23	8
24	17
25	9
26	19
27	10
28	21
29	11
30	23
31	8
32	25
33	13
34	9
35	14
36	29
37	10
38	31
39	8
40	11
41	17
42	35
43	9
44	37
45	19
46	13
47	8
48	41
49	14
50	43
51	11
52	9
53	23
54	47
55	8
56	8
57	8
58	8
59	8
60	8
61	8
62	8
63	8
64	9
65	9
66	9
67	9
68	9
69	9
70	9
71	8
72	10
73	10
74	10
75	10
76	10
77	10
78	10
79	8
80	11
81	11