A175500 - cp's OEIS frontend

A175500 a(1) = 1. a(n) = the smallest integer not yet occurring such that if d(a(n)) = d(a(k)), then d(a(n-1)) doesn't equal d(a(k-1)) for any k where 2<= k <= n-1, where d(m) = the number of divisors of m.

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	12
9	8
10	9
11	10
12	14
13	16
14	11
15	24
16	13
17	36
18	15
19	18
20	17
21	48
22	19
23	60
24	20
25	25
26	28
27	30
28	21
29	40
30	32
31	44
32	64
33	22
34	72
35	23
36	81
37	26
38	80
39	27
40	100
41	29
42	120
43	31
44	144
45	33
46	168
47	34
48	180
49	35
50	192
51	37
52	240
53	38
54	324
55	41
56	252
57	42
58	49
59	54
60	56
61	84
62	39
63	336
64	43

[1, 2, 3, 4, 5, 6, 7, 12, 8, 9, 10, 14, 16, 11, 24, 13, 36, 15, 18, 17, 48, 19, 60, 20, 25, 28, 30, 21, 40, 32, 44, 64, 22, 72, 23, 81, 26, 80, 27, 100, 29, 120, 31, 144, 33, 168, 34, 180, 35, 192, 37, 240, 38, 324, 41, 252, 42, 49, 54, 56, 84, 39, 336, 43]

cp's OEIS Frontend

A175500 a(1) = 1. a(n) = the smallest integer not yet occurring such that if d(a(n)) = d(a(k)), then d(a(n-1)) doesn't equal d(a(k-1)) for any k where 2<= k <= n-1, where d(m) = the number of divisors of m.

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	12
9	8
10	9
11	10
12	14
13	16
14	11
15	24
16	13
17	36
18	15
19	18
20	17
21	48
22	19
23	60
24	20
25	25
26	28
27	30
28	21
29	40
30	32
31	44
32	64
33	22
34	72
35	23
36	81
37	26
38	80
39	27
40	100
41	29
42	120
43	31
44	144
45	33
46	168
47	34
48	180
49	35
50	192
51	37
52	240
53	38
54	324
55	41
56	252
57	42
58	49
59	54
60	56
61	84
62	39
63	336
64	43

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	12
9	8
10	9
11	10
12	14
13	16
14	11
15	24
16	13
17	36
18	15
19	18
20	17
21	48
22	19
23	60
24	20
25	25
26	28
27	30
28	21
29	40
30	32
31	44
32	64
33	22
34	72
35	23
36	81
37	26
38	80
39	27
40	100
41	29
42	120
43	31
44	144
45	33
46	168
47	34
48	180
49	35
50	192
51	37
52	240
53	38
54	324
55	41
56	252
57	42
58	49
59	54
60	56
61	84
62	39
63	336
64	43

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	12
9	8
10	9
11	10
12	14
13	16
14	11
15	24
16	13
17	36
18	15
19	18
20	17
21	48
22	19
23	60
24	20
25	25
26	28
27	30
28	21
29	40
30	32
31	44
32	64
33	22
34	72
35	23
36	81
37	26
38	80
39	27
40	100
41	29
42	120
43	31
44	144
45	33
46	168
47	34
48	180
49	35
50	192
51	37
52	240
53	38
54	324
55	41
56	252
57	42
58	49
59	54
60	56
61	84
62	39
63	336
64	43