A261302 - cp's OEIS frontend

A261302 a(n+1) = abs(a(n) - gcd(a(n), 2n+1)), a(1) = 1.

n	a(n)
1	1
2	0
3	5
4	4
5	3
6	2
7	1
8	0
9	17
10	16
11	15
12	14
13	13
14	12
15	11
16	10
17	9
18	8
19	7
20	6
21	5
22	4
23	3
24	2
25	1
26	0
27	53
28	52
29	51
30	50
31	49
32	42
33	41
34	40
35	39
36	38
37	37
38	36
39	35
40	34
41	33
42	32
43	31
44	30
45	29
46	28
47	27
48	26
49	25
50	24
51	23
52	22
53	21
54	20
55	19
56	18
57	17
58	16
59	15
60	14
61	13
62	12
63	11
64	10
65	9
66	8
67	7
68	6
69	5
70	4
71	3
72	2
73	1
74	0
75	149
76	148
77	147
78	146
79	145
80	144
81	143

[1, 0, 5, 4, 3, 2, 1, 0, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 53, 52, 51, 50, 49, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0, 149, 148, 147, 146, 145, 144, 143]

cp's OEIS Frontend

A261302 a(n+1) = abs(a(n) - gcd(a(n), 2n+1)), a(1) = 1.

Table of values

List of values

n	a(n)
1	1
2	0
3	5
4	4
5	3
6	2
7	1
8	0
9	17
10	16
11	15
12	14
13	13
14	12
15	11
16	10
17	9
18	8
19	7
20	6
21	5
22	4
23	3
24	2
25	1
26	0
27	53
28	52
29	51
30	50
31	49
32	42
33	41
34	40
35	39
36	38
37	37
38	36
39	35
40	34
41	33
42	32
43	31
44	30
45	29
46	28
47	27
48	26
49	25
50	24
51	23
52	22
53	21
54	20
55	19
56	18
57	17
58	16
59	15
60	14
61	13
62	12
63	11
64	10
65	9
66	8
67	7
68	6
69	5
70	4
71	3
72	2
73	1
74	0
75	149
76	148
77	147
78	146
79	145
80	144
81	143

n	a(n)
1	1
2	0
3	5
4	4
5	3
6	2
7	1
8	0
9	17
10	16
11	15
12	14
13	13
14	12
15	11
16	10
17	9
18	8
19	7
20	6
21	5
22	4
23	3
24	2
25	1
26	0
27	53
28	52
29	51
30	50
31	49
32	42
33	41
34	40
35	39
36	38
37	37
38	36
39	35
40	34
41	33
42	32
43	31
44	30
45	29
46	28
47	27
48	26
49	25
50	24
51	23
52	22
53	21
54	20
55	19
56	18
57	17
58	16
59	15
60	14
61	13
62	12
63	11
64	10
65	9
66	8
67	7
68	6
69	5
70	4
71	3
72	2
73	1
74	0
75	149
76	148
77	147
78	146
79	145
80	144
81	143

n	a(n)
1	1
2	0
3	5
4	4
5	3
6	2
7	1
8	0
9	17
10	16
11	15
12	14
13	13
14	12
15	11
16	10
17	9
18	8
19	7
20	6
21	5
22	4
23	3
24	2
25	1
26	0
27	53
28	52
29	51
30	50
31	49
32	42
33	41
34	40
35	39
36	38
37	37
38	36
39	35
40	34
41	33
42	32
43	31
44	30
45	29
46	28
47	27
48	26
49	25
50	24
51	23
52	22
53	21
54	20
55	19
56	18
57	17
58	16
59	15
60	14
61	13
62	12
63	11
64	10
65	9
66	8
67	7
68	6
69	5
70	4
71	3
72	2
73	1
74	0
75	149
76	148
77	147
78	146
79	145
80	144
81	143