A379560 - cp's OEIS frontend

A379560 a(1) = 1, a(2) = 4; for n > 2, a(n) is the smallest unused positive nonsquarefree number that shares a factor with a(n-1).

n	a(n)
1	1
2	4
3	8
4	12
5	9
6	18
7	16
8	20
9	24
10	27
11	36
12	28
13	32
14	40
15	25
16	45
17	48
18	44
19	50
20	52
21	54
22	56
23	49
24	63
25	60
26	64
27	68
28	72
29	75
30	80
31	76
32	84
33	81
34	90
35	88
36	92
37	96
38	98
39	100
40	104
41	108
42	99
43	117
44	120
45	112
46	116
47	124
48	126
49	128
50	132
51	121
52	176
53	136
54	140
55	125
56	135
57	144
58	147
59	150
60	148
61	152
62	156
63	153
64	162
65	160
66	164
67	168
68	171
69	180
70	172
71	184
72	188
73	192
74	189
75	175
76	196
77	198
78	200
79	204
80	207
81	216

[1, 4, 8, 12, 9, 18, 16, 20, 24, 27, 36, 28, 32, 40, 25, 45, 48, 44, 50, 52, 54, 56, 49, 63, 60, 64, 68, 72, 75, 80, 76, 84, 81, 90, 88, 92, 96, 98, 100, 104, 108, 99, 117, 120, 112, 116, 124, 126, 128, 132, 121, 176, 136, 140, 125, 135, 144, 147, 150, 148, 152, 156, 153, 162, 160, 164, 168, 171, 180, 172, 184, 188, 192, 189, 175, 196, 198, 200, 204, 207, 216]

cp's OEIS Frontend

A379560 a(1) = 1, a(2) = 4; for n > 2, a(n) is the smallest unused positive nonsquarefree number that shares a factor with a(n-1).

Table of values

List of values

n	a(n)
1	1
2	4
3	8
4	12
5	9
6	18
7	16
8	20
9	24
10	27
11	36
12	28
13	32
14	40
15	25
16	45
17	48
18	44
19	50
20	52
21	54
22	56
23	49
24	63
25	60
26	64
27	68
28	72
29	75
30	80
31	76
32	84
33	81
34	90
35	88
36	92
37	96
38	98
39	100
40	104
41	108
42	99
43	117
44	120
45	112
46	116
47	124
48	126
49	128
50	132
51	121
52	176
53	136
54	140
55	125
56	135
57	144
58	147
59	150
60	148
61	152
62	156
63	153
64	162
65	160
66	164
67	168
68	171
69	180
70	172
71	184
72	188
73	192
74	189
75	175
76	196
77	198
78	200
79	204
80	207
81	216

n	a(n)
1	1
2	4
3	8
4	12
5	9
6	18
7	16
8	20
9	24
10	27
11	36
12	28
13	32
14	40
15	25
16	45
17	48
18	44
19	50
20	52
21	54
22	56
23	49
24	63
25	60
26	64
27	68
28	72
29	75
30	80
31	76
32	84
33	81
34	90
35	88
36	92
37	96
38	98
39	100
40	104
41	108
42	99
43	117
44	120
45	112
46	116
47	124
48	126
49	128
50	132
51	121
52	176
53	136
54	140
55	125
56	135
57	144
58	147
59	150
60	148
61	152
62	156
63	153
64	162
65	160
66	164
67	168
68	171
69	180
70	172
71	184
72	188
73	192
74	189
75	175
76	196
77	198
78	200
79	204
80	207
81	216

n	a(n)
1	1
2	4
3	8
4	12
5	9
6	18
7	16
8	20
9	24
10	27
11	36
12	28
13	32
14	40
15	25
16	45
17	48
18	44
19	50
20	52
21	54
22	56
23	49
24	63
25	60
26	64
27	68
28	72
29	75
30	80
31	76
32	84
33	81
34	90
35	88
36	92
37	96
38	98
39	100
40	104
41	108
42	99
43	117
44	120
45	112
46	116
47	124
48	126
49	128
50	132
51	121
52	176
53	136
54	140
55	125
56	135
57	144
58	147
59	150
60	148
61	152
62	156
63	153
64	162
65	160
66	164
67	168
68	171
69	180
70	172
71	184
72	188
73	192
74	189
75	175
76	196
77	198
78	200
79	204
80	207
81	216