A074986 - cp's OEIS frontend

A074986 Number of nonempty subsets of {1,2,3,...,n} that are closed under both GCD and LCM.

n	a(n)
1	1
2	3
3	5
4	9
5	11
6	18
7	20
8	28
9	32
10	39
11	41
12	62
13	64
14	71
15	78
16	94
17	96
18	117
19	119
20	140
21	147
22	154
23	156
24	214
25	218
26	225
27	233
28	254
29	256
30	301
31	303
32	335
33	342
34	349
35	356
36	440
37	442
38	449
39	456
40	514
41	516
42	561
43	563
44	584
45	605
46	612
47	614
48	766
49	770
50	791
51	798
52	819
53	821
54	879
55	886
56	944
57	951

[1, 3, 5, 9, 11, 18, 20, 28, 32, 39, 41, 62, 64, 71, 78, 94, 96, 117, 119, 140, 147, 154, 156, 214, 218, 225, 233, 254, 256, 301, 303, 335, 342, 349, 356, 440, 442, 449, 456, 514, 516, 561, 563, 584, 605, 612, 614, 766, 770, 791, 798, 819, 821, 879, 886, 944, 951]

cp's OEIS Frontend

A074986 Number of nonempty subsets of {1,2,3,...,n} that are closed under both GCD and LCM.

Table of values

List of values

n	a(n)
1	1
2	3
3	5
4	9
5	11
6	18
7	20
8	28
9	32
10	39
11	41
12	62
13	64
14	71
15	78
16	94
17	96
18	117
19	119
20	140
21	147
22	154
23	156
24	214
25	218
26	225
27	233
28	254
29	256
30	301
31	303
32	335
33	342
34	349
35	356
36	440
37	442
38	449
39	456
40	514
41	516
42	561
43	563
44	584
45	605
46	612
47	614
48	766
49	770
50	791
51	798
52	819
53	821
54	879
55	886
56	944
57	951

n	a(n)
1	1
2	3
3	5
4	9
5	11
6	18
7	20
8	28
9	32
10	39
11	41
12	62
13	64
14	71
15	78
16	94
17	96
18	117
19	119
20	140
21	147
22	154
23	156
24	214
25	218
26	225
27	233
28	254
29	256
30	301
31	303
32	335
33	342
34	349
35	356
36	440
37	442
38	449
39	456
40	514
41	516
42	561
43	563
44	584
45	605
46	612
47	614
48	766
49	770
50	791
51	798
52	819
53	821
54	879
55	886
56	944
57	951

n	a(n)
1	1
2	3
3	5
4	9
5	11
6	18
7	20
8	28
9	32
10	39
11	41
12	62
13	64
14	71
15	78
16	94
17	96
18	117
19	119
20	140
21	147
22	154
23	156
24	214
25	218
26	225
27	233
28	254
29	256
30	301
31	303
32	335
33	342
34	349
35	356
36	440
37	442
38	449
39	456
40	514
41	516
42	561
43	563
44	584
45	605
46	612
47	614
48	766
49	770
50	791
51	798
52	819
53	821
54	879
55	886
56	944
57	951