A240024 - cp's OEIS frontend

A240024 Nonprime EKG sequence, cf. A064413: a(1) = 1, a(2) = 4 and for n > 2, a(n) = smallest composite number not already used which shares a factor with a(n-1).

n	a(n)
1	1
2	4
3	6
4	8
5	10
6	12
7	9
8	15
9	18
10	14
11	16
12	20
13	22
14	24
15	21
16	27
17	30
18	25
19	35
20	28
21	26
22	32
23	34
24	36
25	33
26	39
27	42
28	38
29	40
30	44
31	46
32	48
33	45
34	50
35	52
36	54
37	51
38	57
39	60
40	55
41	65
42	70
43	49
44	56
45	58
46	62
47	64
48	66
49	63
50	69
51	72
52	68
53	74
54	76
55	78
56	75
57	80
58	82
59	84
60	77
61	88
62	86
63	90
64	81
65	87
66	93

[1, 4, 6, 8, 10, 12, 9, 15, 18, 14, 16, 20, 22, 24, 21, 27, 30, 25, 35, 28, 26, 32, 34, 36, 33, 39, 42, 38, 40, 44, 46, 48, 45, 50, 52, 54, 51, 57, 60, 55, 65, 70, 49, 56, 58, 62, 64, 66, 63, 69, 72, 68, 74, 76, 78, 75, 80, 82, 84, 77, 88, 86, 90, 81, 87, 93]

cp's OEIS Frontend

A240024 Nonprime EKG sequence, cf. A064413: a(1) = 1, a(2) = 4 and for n > 2, a(n) = smallest composite number not already used which shares a factor with a(n-1).

Table of values

List of values

n	a(n)
1	1
2	4
3	6
4	8
5	10
6	12
7	9
8	15
9	18
10	14
11	16
12	20
13	22
14	24
15	21
16	27
17	30
18	25
19	35
20	28
21	26
22	32
23	34
24	36
25	33
26	39
27	42
28	38
29	40
30	44
31	46
32	48
33	45
34	50
35	52
36	54
37	51
38	57
39	60
40	55
41	65
42	70
43	49
44	56
45	58
46	62
47	64
48	66
49	63
50	69
51	72
52	68
53	74
54	76
55	78
56	75
57	80
58	82
59	84
60	77
61	88
62	86
63	90
64	81
65	87
66	93

n	a(n)
1	1
2	4
3	6
4	8
5	10
6	12
7	9
8	15
9	18
10	14
11	16
12	20
13	22
14	24
15	21
16	27
17	30
18	25
19	35
20	28
21	26
22	32
23	34
24	36
25	33
26	39
27	42
28	38
29	40
30	44
31	46
32	48
33	45
34	50
35	52
36	54
37	51
38	57
39	60
40	55
41	65
42	70
43	49
44	56
45	58
46	62
47	64
48	66
49	63
50	69
51	72
52	68
53	74
54	76
55	78
56	75
57	80
58	82
59	84
60	77
61	88
62	86
63	90
64	81
65	87
66	93

n	a(n)
1	1
2	4
3	6
4	8
5	10
6	12
7	9
8	15
9	18
10	14
11	16
12	20
13	22
14	24
15	21
16	27
17	30
18	25
19	35
20	28
21	26
22	32
23	34
24	36
25	33
26	39
27	42
28	38
29	40
30	44
31	46
32	48
33	45
34	50
35	52
36	54
37	51
38	57
39	60
40	55
41	65
42	70
43	49
44	56
45	58
46	62
47	64
48	66
49	63
50	69
51	72
52	68
53	74
54	76
55	78
56	75
57	80
58	82
59	84
60	77
61	88
62	86
63	90
64	81
65	87
66	93