A381526 - cp's OEIS frontend

A381526 a(n) is the smallest positive integer k such that the decimal expansion of k is a substring of the decimal expansion of n*k, or -1 if no such number exists.

n	a(n)
0	-1
1	1
2	-1
3	5
4	-1
5	5
6	2
7	5
8	-1
9	5
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	1
20	-1
21	1
22	9
23	5
24	72
25	5
26	2
27	5
28	6
29	5
30	5
31	1
32	91
33	5
34	42
35	4
36	2
37	4
38	36
39	5
40	-1
41	1
42	94
43	5
44	3
45	3
46	2
47	5
48	8
49	5
50	5
51	1
52	24
53	5
54	7
55	5
56	2
57	5
58	21
59	5
60	2
61	1
62	2
63	2
64	2
65	5
66	2
67	5
68	7
69	5
70	5
71	1
72	484
73	5
74	47
75	5
76	2
77	3
78	3
79	3
80	-1

[-1, 1, -1, 5, -1, 5, 2, 5, -1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 9, 5, 72, 5, 2, 5, 6, 5, 5, 1, 91, 5, 42, 4, 2, 4, 36, 5, -1, 1, 94, 5, 3, 3, 2, 5, 8, 5, 5, 1, 24, 5, 7, 5, 2, 5, 21, 5, 2, 1, 2, 2, 2, 5, 2, 5, 7, 5, 5, 1, 484, 5, 47, 5, 2, 3, 3, 3, -1]

cp's OEIS Frontend

A381526 a(n) is the smallest positive integer k such that the decimal expansion of k is a substring of the decimal expansion of n*k, or -1 if no such number exists.

Table of values

List of values

n	a(n)
0	-1
1	1
2	-1
3	5
4	-1
5	5
6	2
7	5
8	-1
9	5
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	1
20	-1
21	1
22	9
23	5
24	72
25	5
26	2
27	5
28	6
29	5
30	5
31	1
32	91
33	5
34	42
35	4
36	2
37	4
38	36
39	5
40	-1
41	1
42	94
43	5
44	3
45	3
46	2
47	5
48	8
49	5
50	5
51	1
52	24
53	5
54	7
55	5
56	2
57	5
58	21
59	5
60	2
61	1
62	2
63	2
64	2
65	5
66	2
67	5
68	7
69	5
70	5
71	1
72	484
73	5
74	47
75	5
76	2
77	3
78	3
79	3
80	-1

n	a(n)
0	-1
1	1
2	-1
3	5
4	-1
5	5
6	2
7	5
8	-1
9	5
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	1
20	-1
21	1
22	9
23	5
24	72
25	5
26	2
27	5
28	6
29	5
30	5
31	1
32	91
33	5
34	42
35	4
36	2
37	4
38	36
39	5
40	-1
41	1
42	94
43	5
44	3
45	3
46	2
47	5
48	8
49	5
50	5
51	1
52	24
53	5
54	7
55	5
56	2
57	5
58	21
59	5
60	2
61	1
62	2
63	2
64	2
65	5
66	2
67	5
68	7
69	5
70	5
71	1
72	484
73	5
74	47
75	5
76	2
77	3
78	3
79	3
80	-1

n	a(n)
0	-1
1	1
2	-1
3	5
4	-1
5	5
6	2
7	5
8	-1
9	5
10	1
11	1
12	1
13	1
14	1
15	1
16	1
17	1
18	1
19	1
20	-1
21	1
22	9
23	5
24	72
25	5
26	2
27	5
28	6
29	5
30	5
31	1
32	91
33	5
34	42
35	4
36	2
37	4
38	36
39	5
40	-1
41	1
42	94
43	5
44	3
45	3
46	2
47	5
48	8
49	5
50	5
51	1
52	24
53	5
54	7
55	5
56	2
57	5
58	21
59	5
60	2
61	1
62	2
63	2
64	2
65	5
66	2
67	5
68	7
69	5
70	5
71	1
72	484
73	5
74	47
75	5
76	2
77	3
78	3
79	3
80	-1