A340730 - cp's OEIS frontend

A340730 a(0) = 0, a(1) = 1; for n > 1, a(n) = a(n-1) - min(a(n-1),n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + min(a(n-1),n).

n	a(n)
0	0
1	1
2	2
3	4
4	8
5	3
6	6
7	12
8	20
9	11
10	21
11	10
12	20
13	7
14	14
15	28
16	44
17	27
18	9
19	18
20	36
21	15
22	30
23	53
24	29
25	54
26	80
27	107
28	79
29	50
30	80
31	49
32	17
33	34
34	68
35	33
36	66
37	103
38	65
39	26
40	52
41	93
42	51
43	94
44	138
45	183
46	137
47	90
48	42
49	84
50	134
51	83
52	31
53	62
54	116
55	61
56	5
57	10
58	20
59	40
60	80
61	19
62	38
63	76
64	140
65	75
66	141
67	74
68	142
69	73
70	143
71	72
72	144

[0, 1, 2, 4, 8, 3, 6, 12, 20, 11, 21, 10, 20, 7, 14, 28, 44, 27, 9, 18, 36, 15, 30, 53, 29, 54, 80, 107, 79, 50, 80, 49, 17, 34, 68, 33, 66, 103, 65, 26, 52, 93, 51, 94, 138, 183, 137, 90, 42, 84, 134, 83, 31, 62, 116, 61, 5, 10, 20, 40, 80, 19, 38, 76, 140, 75, 141, 74, 142, 73, 143, 72, 144]

cp's OEIS Frontend

A340730 a(0) = 0, a(1) = 1; for n > 1, a(n) = a(n-1) - min(a(n-1),n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + min(a(n-1),n).

Table of values

List of values

n	a(n)
0	0
1	1
2	2
3	4
4	8
5	3
6	6
7	12
8	20
9	11
10	21
11	10
12	20
13	7
14	14
15	28
16	44
17	27
18	9
19	18
20	36
21	15
22	30
23	53
24	29
25	54
26	80
27	107
28	79
29	50
30	80
31	49
32	17
33	34
34	68
35	33
36	66
37	103
38	65
39	26
40	52
41	93
42	51
43	94
44	138
45	183
46	137
47	90
48	42
49	84
50	134
51	83
52	31
53	62
54	116
55	61
56	5
57	10
58	20
59	40
60	80
61	19
62	38
63	76
64	140
65	75
66	141
67	74
68	142
69	73
70	143
71	72
72	144

n	a(n)
0	0
1	1
2	2
3	4
4	8
5	3
6	6
7	12
8	20
9	11
10	21
11	10
12	20
13	7
14	14
15	28
16	44
17	27
18	9
19	18
20	36
21	15
22	30
23	53
24	29
25	54
26	80
27	107
28	79
29	50
30	80
31	49
32	17
33	34
34	68
35	33
36	66
37	103
38	65
39	26
40	52
41	93
42	51
43	94
44	138
45	183
46	137
47	90
48	42
49	84
50	134
51	83
52	31
53	62
54	116
55	61
56	5
57	10
58	20
59	40
60	80
61	19
62	38
63	76
64	140
65	75
66	141
67	74
68	142
69	73
70	143
71	72
72	144

n	a(n)
0	0
1	1
2	2
3	4
4	8
5	3
6	6
7	12
8	20
9	11
10	21
11	10
12	20
13	7
14	14
15	28
16	44
17	27
18	9
19	18
20	36
21	15
22	30
23	53
24	29
25	54
26	80
27	107
28	79
29	50
30	80
31	49
32	17
33	34
34	68
35	33
36	66
37	103
38	65
39	26
40	52
41	93
42	51
43	94
44	138
45	183
46	137
47	90
48	42
49	84
50	134
51	83
52	31
53	62
54	116
55	61
56	5
57	10
58	20
59	40
60	80
61	19
62	38
63	76
64	140
65	75
66	141
67	74
68	142
69	73
70	143
71	72
72	144