A329850 - cp's OEIS frontend

A329850 Lexicographically earliest sequence of distinct positive integers such that for any n > 0, f(n) * f(a(n)) = f(n * a(n)) where f(m) is the product of the digits of m.

n	a(n)
1	1
2	2
3	3
4	10
5	19
6	20
7	30
8	40
9	50
10	4
11	60
12	70
13	18
14	46
15	80
16	90
17	100
18	13
19	5
20	6
21	64
22	61
23	28
24	72
25	102
26	104
27	62
28	23
29	41
30	7
31	110
32	42
33	120
34	103
35	106
36	105
37	109
38	107
39	130
40	8
41	29
42	32
43	140
44	150
45	108
46	14
47	160
48	170
49	180
50	9
51	190
52	200
53	201
54	202
55	83
56	205
57	210
58	148
59	204
60	11
61	22

[1, 2, 3, 10, 19, 20, 30, 40, 50, 4, 60, 70, 18, 46, 80, 90, 100, 13, 5, 6, 64, 61, 28, 72, 102, 104, 62, 23, 41, 7, 110, 42, 120, 103, 106, 105, 109, 107, 130, 8, 29, 32, 140, 150, 108, 14, 160, 170, 180, 9, 190, 200, 201, 202, 83, 205, 210, 148, 204, 11, 22]

cp's OEIS Frontend

A329850 Lexicographically earliest sequence of distinct positive integers such that for any n > 0, f(n) * f(a(n)) = f(n * a(n)) where f(m) is the product of the digits of m.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	10
5	19
6	20
7	30
8	40
9	50
10	4
11	60
12	70
13	18
14	46
15	80
16	90
17	100
18	13
19	5
20	6
21	64
22	61
23	28
24	72
25	102
26	104
27	62
28	23
29	41
30	7
31	110
32	42
33	120
34	103
35	106
36	105
37	109
38	107
39	130
40	8
41	29
42	32
43	140
44	150
45	108
46	14
47	160
48	170
49	180
50	9
51	190
52	200
53	201
54	202
55	83
56	205
57	210
58	148
59	204
60	11
61	22

n	a(n)
1	1
2	2
3	3
4	10
5	19
6	20
7	30
8	40
9	50
10	4
11	60
12	70
13	18
14	46
15	80
16	90
17	100
18	13
19	5
20	6
21	64
22	61
23	28
24	72
25	102
26	104
27	62
28	23
29	41
30	7
31	110
32	42
33	120
34	103
35	106
36	105
37	109
38	107
39	130
40	8
41	29
42	32
43	140
44	150
45	108
46	14
47	160
48	170
49	180
50	9
51	190
52	200
53	201
54	202
55	83
56	205
57	210
58	148
59	204
60	11
61	22

n	a(n)
1	1
2	2
3	3
4	10
5	19
6	20
7	30
8	40
9	50
10	4
11	60
12	70
13	18
14	46
15	80
16	90
17	100
18	13
19	5
20	6
21	64
22	61
23	28
24	72
25	102
26	104
27	62
28	23
29	41
30	7
31	110
32	42
33	120
34	103
35	106
36	105
37	109
38	107
39	130
40	8
41	29
42	32
43	140
44	150
45	108
46	14
47	160
48	170
49	180
50	9
51	190
52	200
53	201
54	202
55	83
56	205
57	210
58	148
59	204
60	11
61	22