A088230 - cp's OEIS frontend

A088230 a(1)=0; for n>1: a(n)=a(n-1)-n if that number is nonnegative and occurs at most once in the sequence, otherwise a(n)=a(n-1)+n.

n	a(n)
1	0
2	1
3	3
4	0
5	4
6	9
7	3
8	10
9	2
10	11
11	1
12	12
13	24
14	11
15	25
16	10
17	26
18	9
19	27
20	8
21	28
22	7
23	29
24	6
25	30
26	5
27	31
28	4
29	32
30	61
31	31
32	62
33	30
34	63
35	29
36	64
37	28
38	65
39	27
40	66
41	26
42	67
43	25
44	68
45	24
46	69
47	23
48	70
49	22
50	71
51	21
52	72
53	20
54	73
55	19
56	74
57	18
58	75
59	17
60	76
61	16
62	77
63	15
64	78
65	14
66	79
67	13
68	80
69	12
70	81
71	151
72	80
73	8
74	81

[0, 1, 3, 0, 4, 9, 3, 10, 2, 11, 1, 12, 24, 11, 25, 10, 26, 9, 27, 8, 28, 7, 29, 6, 30, 5, 31, 4, 32, 61, 31, 62, 30, 63, 29, 64, 28, 65, 27, 66, 26, 67, 25, 68, 24, 69, 23, 70, 22, 71, 21, 72, 20, 73, 19, 74, 18, 75, 17, 76, 16, 77, 15, 78, 14, 79, 13, 80, 12, 81, 151, 80, 8, 81]

cp's OEIS Frontend

A088230 a(1)=0; for n>1: a(n)=a(n-1)-n if that number is nonnegative and occurs at most once in the sequence, otherwise a(n)=a(n-1)+n.

Table of values

List of values

n	a(n)
1	0
2	1
3	3
4	0
5	4
6	9
7	3
8	10
9	2
10	11
11	1
12	12
13	24
14	11
15	25
16	10
17	26
18	9
19	27
20	8
21	28
22	7
23	29
24	6
25	30
26	5
27	31
28	4
29	32
30	61
31	31
32	62
33	30
34	63
35	29
36	64
37	28
38	65
39	27
40	66
41	26
42	67
43	25
44	68
45	24
46	69
47	23
48	70
49	22
50	71
51	21
52	72
53	20
54	73
55	19
56	74
57	18
58	75
59	17
60	76
61	16
62	77
63	15
64	78
65	14
66	79
67	13
68	80
69	12
70	81
71	151
72	80
73	8
74	81

n	a(n)
1	0
2	1
3	3
4	0
5	4
6	9
7	3
8	10
9	2
10	11
11	1
12	12
13	24
14	11
15	25
16	10
17	26
18	9
19	27
20	8
21	28
22	7
23	29
24	6
25	30
26	5
27	31
28	4
29	32
30	61
31	31
32	62
33	30
34	63
35	29
36	64
37	28
38	65
39	27
40	66
41	26
42	67
43	25
44	68
45	24
46	69
47	23
48	70
49	22
50	71
51	21
52	72
53	20
54	73
55	19
56	74
57	18
58	75
59	17
60	76
61	16
62	77
63	15
64	78
65	14
66	79
67	13
68	80
69	12
70	81
71	151
72	80
73	8
74	81

n	a(n)
1	0
2	1
3	3
4	0
5	4
6	9
7	3
8	10
9	2
10	11
11	1
12	12
13	24
14	11
15	25
16	10
17	26
18	9
19	27
20	8
21	28
22	7
23	29
24	6
25	30
26	5
27	31
28	4
29	32
30	61
31	31
32	62
33	30
34	63
35	29
36	64
37	28
38	65
39	27
40	66
41	26
42	67
43	25
44	68
45	24
46	69
47	23
48	70
49	22
50	71
51	21
52	72
53	20
54	73
55	19
56	74
57	18
58	75
59	17
60	76
61	16
62	77
63	15
64	78
65	14
66	79
67	13
68	80
69	12
70	81
71	151
72	80
73	8
74	81