A066203 - cp's OEIS frontend

A066203 a(1) = 2; a(2) = 1; for n > 2, a(n) = a(n-1)-(n-1) if this is positive and has not already appeared in the sequence, otherwise a(n) = a(n-1)+(n-1).

n	a(n)
1	2
2	1
3	3
4	6
5	10
6	5
7	11
8	4
9	12
10	21
11	31
12	20
13	8
14	21
15	7
16	22
17	38
18	55
19	37
20	18
21	38
22	17
23	39
24	16
25	40
26	15
27	41
28	14
29	42
30	13
31	43
32	74
33	106
34	73
35	107
36	72
37	36
38	73
39	35
40	74
41	34
42	75
43	33
44	76
45	32
46	77
47	123
48	170
49	122
50	171
51	121
52	70
53	122
54	69
55	123
56	68
57	124
58	67
59	9
60	68
61	128
62	189
63	127
64	64
65	128
66	63
67	129
68	62

[2, 1, 3, 6, 10, 5, 11, 4, 12, 21, 31, 20, 8, 21, 7, 22, 38, 55, 37, 18, 38, 17, 39, 16, 40, 15, 41, 14, 42, 13, 43, 74, 106, 73, 107, 72, 36, 73, 35, 74, 34, 75, 33, 76, 32, 77, 123, 170, 122, 171, 121, 70, 122, 69, 123, 68, 124, 67, 9, 68, 128, 189, 127, 64, 128, 63, 129, 62]

cp's OEIS Frontend

A066203 a(1) = 2; a(2) = 1; for n > 2, a(n) = a(n-1)-(n-1) if this is positive and has not already appeared in the sequence, otherwise a(n) = a(n-1)+(n-1).

Table of values

List of values

n	a(n)
1	2
2	1
3	3
4	6
5	10
6	5
7	11
8	4
9	12
10	21
11	31
12	20
13	8
14	21
15	7
16	22
17	38
18	55
19	37
20	18
21	38
22	17
23	39
24	16
25	40
26	15
27	41
28	14
29	42
30	13
31	43
32	74
33	106
34	73
35	107
36	72
37	36
38	73
39	35
40	74
41	34
42	75
43	33
44	76
45	32
46	77
47	123
48	170
49	122
50	171
51	121
52	70
53	122
54	69
55	123
56	68
57	124
58	67
59	9
60	68
61	128
62	189
63	127
64	64
65	128
66	63
67	129
68	62

n	a(n)
1	2
2	1
3	3
4	6
5	10
6	5
7	11
8	4
9	12
10	21
11	31
12	20
13	8
14	21
15	7
16	22
17	38
18	55
19	37
20	18
21	38
22	17
23	39
24	16
25	40
26	15
27	41
28	14
29	42
30	13
31	43
32	74
33	106
34	73
35	107
36	72
37	36
38	73
39	35
40	74
41	34
42	75
43	33
44	76
45	32
46	77
47	123
48	170
49	122
50	171
51	121
52	70
53	122
54	69
55	123
56	68
57	124
58	67
59	9
60	68
61	128
62	189
63	127
64	64
65	128
66	63
67	129
68	62

n	a(n)
1	2
2	1
3	3
4	6
5	10
6	5
7	11
8	4
9	12
10	21
11	31
12	20
13	8
14	21
15	7
16	22
17	38
18	55
19	37
20	18
21	38
22	17
23	39
24	16
25	40
26	15
27	41
28	14
29	42
30	13
31	43
32	74
33	106
34	73
35	107
36	72
37	36
38	73
39	35
40	74
41	34
42	75
43	33
44	76
45	32
46	77
47	123
48	170
49	122
50	171
51	121
52	70
53	122
54	69
55	123
56	68
57	124
58	67
59	9
60	68
61	128
62	189
63	127
64	64
65	128
66	63
67	129
68	62