A355617 - cp's OEIS frontend

A355617 a(1) = 1; a(2) = 2; for n > 2, a(n) = R(a(n-1)) if a(n-1) != R(a(n-2)) and R(a(n-1)) has not yet been used, where R is the digit reversal function A004086, otherwise a(n) is the smallest positive integer > a(n-1) that has not yet been used.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	10
11	11
12	12
13	21
14	22
15	23
16	32
17	33
18	34
19	43
20	44
21	45
22	54
23	55
24	56
25	65
26	66
27	67
28	76
29	77
30	78
31	87
32	88
33	89
34	98
35	99
36	100
37	101
38	102
39	201
40	202
41	203
42	302
43	303
44	304
45	403
46	404
47	405
48	504
49	505
50	506
51	605
52	606
53	607
54	706
55	707
56	708
57	807
58	808
59	809
60	908
61	909

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 21, 22, 23, 32, 33, 34, 43, 44, 45, 54, 55, 56, 65, 66, 67, 76, 77, 78, 87, 88, 89, 98, 99, 100, 101, 102, 201, 202, 203, 302, 303, 304, 403, 404, 405, 504, 505, 506, 605, 606, 607, 706, 707, 708, 807, 808, 809, 908, 909]

cp's OEIS Frontend

A355617 a(1) = 1; a(2) = 2; for n > 2, a(n) = R(a(n-1)) if a(n-1) != R(a(n-2)) and R(a(n-1)) has not yet been used, where R is the digit reversal function A004086, otherwise a(n) is the smallest positive integer > a(n-1) that has not yet been used.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	10
11	11
12	12
13	21
14	22
15	23
16	32
17	33
18	34
19	43
20	44
21	45
22	54
23	55
24	56
25	65
26	66
27	67
28	76
29	77
30	78
31	87
32	88
33	89
34	98
35	99
36	100
37	101
38	102
39	201
40	202
41	203
42	302
43	303
44	304
45	403
46	404
47	405
48	504
49	505
50	506
51	605
52	606
53	607
54	706
55	707
56	708
57	807
58	808
59	809
60	908
61	909

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	10
11	11
12	12
13	21
14	22
15	23
16	32
17	33
18	34
19	43
20	44
21	45
22	54
23	55
24	56
25	65
26	66
27	67
28	76
29	77
30	78
31	87
32	88
33	89
34	98
35	99
36	100
37	101
38	102
39	201
40	202
41	203
42	302
43	303
44	304
45	403
46	404
47	405
48	504
49	505
50	506
51	605
52	606
53	607
54	706
55	707
56	708
57	807
58	808
59	809
60	908
61	909

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	10
11	11
12	12
13	21
14	22
15	23
16	32
17	33
18	34
19	43
20	44
21	45
22	54
23	55
24	56
25	65
26	66
27	67
28	76
29	77
30	78
31	87
32	88
33	89
34	98
35	99
36	100
37	101
38	102
39	201
40	202
41	203
42	302
43	303
44	304
45	403
46	404
47	405
48	504
49	505
50	506
51	605
52	606
53	607
54	706
55	707
56	708
57	807
58	808
59	809
60	908
61	909