A066204 - cp's OEIS frontend

A066204 a(1) = 4; a(2) = 3; a(3) = 1; for n > 3, 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	4
2	3
3	1
4	4
5	8
6	13
7	7
8	14
9	6
10	15
11	5
12	16
13	28
14	41
15	27
16	12
17	28
18	11
19	29
20	10
21	30
22	9
23	31
24	54
25	78
26	53
27	79
28	52
29	24
30	53
31	23
32	54
33	22
34	55
35	21
36	56
37	20
38	57
39	19
40	58
41	18
42	59
43	17
44	60
45	104
46	149
47	103
48	150
49	102
50	151
51	101
52	50
53	102
54	49
55	103
56	48
57	104
58	47
59	105
60	46
61	106
62	45
63	107
64	44
65	108
66	43
67	109

[4, 3, 1, 4, 8, 13, 7, 14, 6, 15, 5, 16, 28, 41, 27, 12, 28, 11, 29, 10, 30, 9, 31, 54, 78, 53, 79, 52, 24, 53, 23, 54, 22, 55, 21, 56, 20, 57, 19, 58, 18, 59, 17, 60, 104, 149, 103, 150, 102, 151, 101, 50, 102, 49, 103, 48, 104, 47, 105, 46, 106, 45, 107, 44, 108, 43, 109]

cp's OEIS Frontend

A066204 a(1) = 4; a(2) = 3; a(3) = 1; for n > 3, 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	4
2	3
3	1
4	4
5	8
6	13
7	7
8	14
9	6
10	15
11	5
12	16
13	28
14	41
15	27
16	12
17	28
18	11
19	29
20	10
21	30
22	9
23	31
24	54
25	78
26	53
27	79
28	52
29	24
30	53
31	23
32	54
33	22
34	55
35	21
36	56
37	20
38	57
39	19
40	58
41	18
42	59
43	17
44	60
45	104
46	149
47	103
48	150
49	102
50	151
51	101
52	50
53	102
54	49
55	103
56	48
57	104
58	47
59	105
60	46
61	106
62	45
63	107
64	44
65	108
66	43
67	109

n	a(n)
1	4
2	3
3	1
4	4
5	8
6	13
7	7
8	14
9	6
10	15
11	5
12	16
13	28
14	41
15	27
16	12
17	28
18	11
19	29
20	10
21	30
22	9
23	31
24	54
25	78
26	53
27	79
28	52
29	24
30	53
31	23
32	54
33	22
34	55
35	21
36	56
37	20
38	57
39	19
40	58
41	18
42	59
43	17
44	60
45	104
46	149
47	103
48	150
49	102
50	151
51	101
52	50
53	102
54	49
55	103
56	48
57	104
58	47
59	105
60	46
61	106
62	45
63	107
64	44
65	108
66	43
67	109

n	a(n)
1	4
2	3
3	1
4	4
5	8
6	13
7	7
8	14
9	6
10	15
11	5
12	16
13	28
14	41
15	27
16	12
17	28
18	11
19	29
20	10
21	30
22	9
23	31
24	54
25	78
26	53
27	79
28	52
29	24
30	53
31	23
32	54
33	22
34	55
35	21
36	56
37	20
38	57
39	19
40	58
41	18
42	59
43	17
44	60
45	104
46	149
47	103
48	150
49	102
50	151
51	101
52	50
53	102
54	49
55	103
56	48
57	104
58	47
59	105
60	46
61	106
62	45
63	107
64	44
65	108
66	43
67	109