A125886 - cp's OEIS frontend

A125886 a(1) = 1, a(n) = smallest positive number b not among a(1)..a(n-1) such that the last digit of b = the first digit of a(n-1).

n	a(n)
1	1
2	11
3	21
4	12
5	31
6	13
7	41
8	14
9	51
10	15
11	61
12	16
13	71
14	17
15	81
16	18
17	91
18	19
19	101
20	111
21	121
22	131
23	141
24	151
25	161
26	171
27	181
28	191
29	201
30	22
31	32
32	23
33	42
34	24
35	52
36	25
37	62
38	26
39	72
40	27
41	82
42	28
43	92
44	29
45	102
46	211
47	112
48	221
49	122
50	231
51	132
52	241
53	142
54	251
55	152
56	261
57	162
58	271
59	172
60	281
61	182

[1, 11, 21, 12, 31, 13, 41, 14, 51, 15, 61, 16, 71, 17, 81, 18, 91, 19, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, 201, 22, 32, 23, 42, 24, 52, 25, 62, 26, 72, 27, 82, 28, 92, 29, 102, 211, 112, 221, 122, 231, 132, 241, 142, 251, 152, 261, 162, 271, 172, 281, 182]

cp's OEIS Frontend

A125886 a(1) = 1, a(n) = smallest positive number b not among a(1)..a(n-1) such that the last digit of b = the first digit of a(n-1).

Table of values

List of values

n	a(n)
1	1
2	11
3	21
4	12
5	31
6	13
7	41
8	14
9	51
10	15
11	61
12	16
13	71
14	17
15	81
16	18
17	91
18	19
19	101
20	111
21	121
22	131
23	141
24	151
25	161
26	171
27	181
28	191
29	201
30	22
31	32
32	23
33	42
34	24
35	52
36	25
37	62
38	26
39	72
40	27
41	82
42	28
43	92
44	29
45	102
46	211
47	112
48	221
49	122
50	231
51	132
52	241
53	142
54	251
55	152
56	261
57	162
58	271
59	172
60	281
61	182

n	a(n)
1	1
2	11
3	21
4	12
5	31
6	13
7	41
8	14
9	51
10	15
11	61
12	16
13	71
14	17
15	81
16	18
17	91
18	19
19	101
20	111
21	121
22	131
23	141
24	151
25	161
26	171
27	181
28	191
29	201
30	22
31	32
32	23
33	42
34	24
35	52
36	25
37	62
38	26
39	72
40	27
41	82
42	28
43	92
44	29
45	102
46	211
47	112
48	221
49	122
50	231
51	132
52	241
53	142
54	251
55	152
56	261
57	162
58	271
59	172
60	281
61	182

n	a(n)
1	1
2	11
3	21
4	12
5	31
6	13
7	41
8	14
9	51
10	15
11	61
12	16
13	71
14	17
15	81
16	18
17	91
18	19
19	101
20	111
21	121
22	131
23	141
24	151
25	161
26	171
27	181
28	191
29	201
30	22
31	32
32	23
33	42
34	24
35	52
36	25
37	62
38	26
39	72
40	27
41	82
42	28
43	92
44	29
45	102
46	211
47	112
48	221
49	122
50	231
51	132
52	241
53	142
54	251
55	152
56	261
57	162
58	271
59	172
60	281
61	182