A261573 - cp's OEIS frontend

A261573 A variation of Recamán's sequence A005132: Define a(0) = 0, and for n > 0, a(n) = a(n-1) - (n+2) if positive and not already in the sequence, otherwise a(n) = a(n-1) + (n+2).

n	a(n)
0	0
1	3
2	7
3	2
4	8
5	1
6	9
7	18
8	28
9	17
10	5
11	18
12	4
13	19
14	35
15	52
16	34
17	15
18	35
19	14
20	36
21	13
22	37
23	12
24	38
25	11
26	39
27	10
28	40
29	71
30	103
31	70
32	104
33	69
34	33
35	70
36	32
37	71
38	31
39	72
40	30
41	73
42	29
43	74
44	120
45	167
46	119
47	168
48	118
49	67
50	119
51	66
52	120
53	65
54	121
55	64
56	6
57	65
58	125
59	186
60	124
61	61
62	125
63	60
64	126
65	59
66	127
67	58
68	128
69	57

[0, 3, 7, 2, 8, 1, 9, 18, 28, 17, 5, 18, 4, 19, 35, 52, 34, 15, 35, 14, 36, 13, 37, 12, 38, 11, 39, 10, 40, 71, 103, 70, 104, 69, 33, 70, 32, 71, 31, 72, 30, 73, 29, 74, 120, 167, 119, 168, 118, 67, 119, 66, 120, 65, 121, 64, 6, 65, 125, 186, 124, 61, 125, 60, 126, 59, 127, 58, 128, 57]

cp's OEIS Frontend

A261573 A variation of Recamán's sequence A005132: Define a(0) = 0, and for n > 0, a(n) = a(n-1) - (n+2) if positive and not already in the sequence, otherwise a(n) = a(n-1) + (n+2).

Table of values

List of values

n	a(n)
0	0
1	3
2	7
3	2
4	8
5	1
6	9
7	18
8	28
9	17
10	5
11	18
12	4
13	19
14	35
15	52
16	34
17	15
18	35
19	14
20	36
21	13
22	37
23	12
24	38
25	11
26	39
27	10
28	40
29	71
30	103
31	70
32	104
33	69
34	33
35	70
36	32
37	71
38	31
39	72
40	30
41	73
42	29
43	74
44	120
45	167
46	119
47	168
48	118
49	67
50	119
51	66
52	120
53	65
54	121
55	64
56	6
57	65
58	125
59	186
60	124
61	61
62	125
63	60
64	126
65	59
66	127
67	58
68	128
69	57

n	a(n)
0	0
1	3
2	7
3	2
4	8
5	1
6	9
7	18
8	28
9	17
10	5
11	18
12	4
13	19
14	35
15	52
16	34
17	15
18	35
19	14
20	36
21	13
22	37
23	12
24	38
25	11
26	39
27	10
28	40
29	71
30	103
31	70
32	104
33	69
34	33
35	70
36	32
37	71
38	31
39	72
40	30
41	73
42	29
43	74
44	120
45	167
46	119
47	168
48	118
49	67
50	119
51	66
52	120
53	65
54	121
55	64
56	6
57	65
58	125
59	186
60	124
61	61
62	125
63	60
64	126
65	59
66	127
67	58
68	128
69	57

n	a(n)
0	0
1	3
2	7
3	2
4	8
5	1
6	9
7	18
8	28
9	17
10	5
11	18
12	4
13	19
14	35
15	52
16	34
17	15
18	35
19	14
20	36
21	13
22	37
23	12
24	38
25	11
26	39
27	10
28	40
29	71
30	103
31	70
32	104
33	69
34	33
35	70
36	32
37	71
38	31
39	72
40	30
41	73
42	29
43	74
44	120
45	167
46	119
47	168
48	118
49	67
50	119
51	66
52	120
53	65
54	121
55	64
56	6
57	65
58	125
59	186
60	124
61	61
62	125
63	60
64	126
65	59
66	127
67	58
68	128
69	57