A354755 - cp's OEIS frontend

A354755 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number that shares a factor with a(n-1) and the sum a(n) + a(n-1) is distinct from all previous sums a(i) + a(i-1), i=2..n-1.

n	a(n)
1	1
2	2
3	2
4	4
5	4
6	6
7	3
8	9
9	6
10	8
11	8
12	10
13	10
14	12
15	9
16	15
17	10
18	16
19	12
20	15
21	15
22	18
23	14
24	20
25	15
26	21
27	18
28	20
29	20
30	22
31	22
32	24
33	21
34	27
35	24
36	26
37	26
38	28
39	21
40	35
41	20
42	38
43	19
44	57
45	3
46	60
47	2
48	62
49	4
50	64
51	6
52	63
53	9
54	66
55	8
56	70
57	7
58	77
59	11
60	88
61	2
62	78
63	3
64	84
65	2
66	80
67	5
68	60
69	32
70	62
71	31
72	93
73	3
74	99
75	6
76	92
77	8
78	96
79	10
80	85
81	25

[1, 2, 2, 4, 4, 6, 3, 9, 6, 8, 8, 10, 10, 12, 9, 15, 10, 16, 12, 15, 15, 18, 14, 20, 15, 21, 18, 20, 20, 22, 22, 24, 21, 27, 24, 26, 26, 28, 21, 35, 20, 38, 19, 57, 3, 60, 2, 62, 4, 64, 6, 63, 9, 66, 8, 70, 7, 77, 11, 88, 2, 78, 3, 84, 2, 80, 5, 60, 32, 62, 31, 93, 3, 99, 6, 92, 8, 96, 10, 85, 25]

cp's OEIS Frontend

A354755 a(1) = 1, a(2) = 2; for n > 2, a(n) is the smallest positive number that shares a factor with a(n-1) and the sum a(n) + a(n-1) is distinct from all previous sums a(i) + a(i-1), i=2..n-1.

Table of values

List of values

n	a(n)
1	1
2	2
3	2
4	4
5	4
6	6
7	3
8	9
9	6
10	8
11	8
12	10
13	10
14	12
15	9
16	15
17	10
18	16
19	12
20	15
21	15
22	18
23	14
24	20
25	15
26	21
27	18
28	20
29	20
30	22
31	22
32	24
33	21
34	27
35	24
36	26
37	26
38	28
39	21
40	35
41	20
42	38
43	19
44	57
45	3
46	60
47	2
48	62
49	4
50	64
51	6
52	63
53	9
54	66
55	8
56	70
57	7
58	77
59	11
60	88
61	2
62	78
63	3
64	84
65	2
66	80
67	5
68	60
69	32
70	62
71	31
72	93
73	3
74	99
75	6
76	92
77	8
78	96
79	10
80	85
81	25

n	a(n)
1	1
2	2
3	2
4	4
5	4
6	6
7	3
8	9
9	6
10	8
11	8
12	10
13	10
14	12
15	9
16	15
17	10
18	16
19	12
20	15
21	15
22	18
23	14
24	20
25	15
26	21
27	18
28	20
29	20
30	22
31	22
32	24
33	21
34	27
35	24
36	26
37	26
38	28
39	21
40	35
41	20
42	38
43	19
44	57
45	3
46	60
47	2
48	62
49	4
50	64
51	6
52	63
53	9
54	66
55	8
56	70
57	7
58	77
59	11
60	88
61	2
62	78
63	3
64	84
65	2
66	80
67	5
68	60
69	32
70	62
71	31
72	93
73	3
74	99
75	6
76	92
77	8
78	96
79	10
80	85
81	25

n	a(n)
1	1
2	2
3	2
4	4
5	4
6	6
7	3
8	9
9	6
10	8
11	8
12	10
13	10
14	12
15	9
16	15
17	10
18	16
19	12
20	15
21	15
22	18
23	14
24	20
25	15
26	21
27	18
28	20
29	20
30	22
31	22
32	24
33	21
34	27
35	24
36	26
37	26
38	28
39	21
40	35
41	20
42	38
43	19
44	57
45	3
46	60
47	2
48	62
49	4
50	64
51	6
52	63
53	9
54	66
55	8
56	70
57	7
58	77
59	11
60	88
61	2
62	78
63	3
64	84
65	2
66	80
67	5
68	60
69	32
70	62
71	31
72	93
73	3
74	99
75	6
76	92
77	8
78	96
79	10
80	85
81	25