A336946 - cp's OEIS frontend

A336946 a(1) = 1; for n > 1, a(n) is the next square spiral number not already used such that a(n) shares a factor with a(n-1) and also with the adjacent number on the inner spiral arm if such a number exists.

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	20
12	14
13	7
14	28
15	16
16	18
17	15
18	21
19	24
20	22
21	11
22	33
23	30
24	25
25	35
26	40
27	45
28	36
29	26
30	42
31	27
32	63
33	48
34	32
35	34
36	50
37	38
38	54
39	39
40	51
41	60
42	44
43	46
44	66
45	55
46	65
47	70
48	49
49	56
50	52
51	58
52	72
53	57
54	76
55	62
56	78
57	13
58	117
59	69
60	75
61	80
62	64
63	68
64	74
65	37
66	148

[1, 2, 4, 6, 3, 9, 12, 8, 10, 5, 20, 14, 7, 28, 16, 18, 15, 21, 24, 22, 11, 33, 30, 25, 35, 40, 45, 36, 26, 42, 27, 63, 48, 32, 34, 50, 38, 54, 39, 51, 60, 44, 46, 66, 55, 65, 70, 49, 56, 52, 58, 72, 57, 76, 62, 78, 13, 117, 69, 75, 80, 64, 68, 74, 37, 148]

cp's OEIS Frontend

A336946 a(1) = 1; for n > 1, a(n) is the next square spiral number not already used such that a(n) shares a factor with a(n-1) and also with the adjacent number on the inner spiral arm if such a number exists.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	20
12	14
13	7
14	28
15	16
16	18
17	15
18	21
19	24
20	22
21	11
22	33
23	30
24	25
25	35
26	40
27	45
28	36
29	26
30	42
31	27
32	63
33	48
34	32
35	34
36	50
37	38
38	54
39	39
40	51
41	60
42	44
43	46
44	66
45	55
46	65
47	70
48	49
49	56
50	52
51	58
52	72
53	57
54	76
55	62
56	78
57	13
58	117
59	69
60	75
61	80
62	64
63	68
64	74
65	37
66	148

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	20
12	14
13	7
14	28
15	16
16	18
17	15
18	21
19	24
20	22
21	11
22	33
23	30
24	25
25	35
26	40
27	45
28	36
29	26
30	42
31	27
32	63
33	48
34	32
35	34
36	50
37	38
38	54
39	39
40	51
41	60
42	44
43	46
44	66
45	55
46	65
47	70
48	49
49	56
50	52
51	58
52	72
53	57
54	76
55	62
56	78
57	13
58	117
59	69
60	75
61	80
62	64
63	68
64	74
65	37
66	148

n	a(n)
1	1
2	2
3	4
4	6
5	3
6	9
7	12
8	8
9	10
10	5
11	20
12	14
13	7
14	28
15	16
16	18
17	15
18	21
19	24
20	22
21	11
22	33
23	30
24	25
25	35
26	40
27	45
28	36
29	26
30	42
31	27
32	63
33	48
34	32
35	34
36	50
37	38
38	54
39	39
40	51
41	60
42	44
43	46
44	66
45	55
46	65
47	70
48	49
49	56
50	52
51	58
52	72
53	57
54	76
55	62
56	78
57	13
58	117
59	69
60	75
61	80
62	64
63	68
64	74
65	37
66	148