A332056 - cp's OEIS frontend

A332056 a(1) = 1, then a(n+1) = a(n) - (-1)^a(n) Sum_{k=1..n} a(k): if a(n) is odd, add the partial sum, else subtract.

n	a(n)
1	1
2	2
3	-1
4	1
5	4
6	-3
7	1
8	6
9	-5
10	1
11	8
12	-7
13	1
14	10
15	-9
16	1
17	12
18	-11
19	1
20	14
21	-13
22	1
23	16
24	-15
25	1
26	18
27	-17
28	1
29	20
30	-19
31	1
32	22
33	-21
34	1
35	24
36	-23
37	1
38	26
39	-25
40	1
41	28
42	-27
43	1
44	30
45	-29
46	1
47	32
48	-31
49	1
50	34
51	-33
52	1
53	36
54	-35
55	1
56	38
57	-37
58	1
59	40
60	-39

[1, 2, -1, 1, 4, -3, 1, 6, -5, 1, 8, -7, 1, 10, -9, 1, 12, -11, 1, 14, -13, 1, 16, -15, 1, 18, -17, 1, 20, -19, 1, 22, -21, 1, 24, -23, 1, 26, -25, 1, 28, -27, 1, 30, -29, 1, 32, -31, 1, 34, -33, 1, 36, -35, 1, 38, -37, 1, 40, -39]

cp's OEIS Frontend

A332056 a(1) = 1, then a(n+1) = a(n) - (-1)^a(n) Sum_{k=1..n} a(k): if a(n) is odd, add the partial sum, else subtract.

Table of values

List of values

n	a(n)
1	1
2	2
3	-1
4	1
5	4
6	-3
7	1
8	6
9	-5
10	1
11	8
12	-7
13	1
14	10
15	-9
16	1
17	12
18	-11
19	1
20	14
21	-13
22	1
23	16
24	-15
25	1
26	18
27	-17
28	1
29	20
30	-19
31	1
32	22
33	-21
34	1
35	24
36	-23
37	1
38	26
39	-25
40	1
41	28
42	-27
43	1
44	30
45	-29
46	1
47	32
48	-31
49	1
50	34
51	-33
52	1
53	36
54	-35
55	1
56	38
57	-37
58	1
59	40
60	-39

n	a(n)
1	1
2	2
3	-1
4	1
5	4
6	-3
7	1
8	6
9	-5
10	1
11	8
12	-7
13	1
14	10
15	-9
16	1
17	12
18	-11
19	1
20	14
21	-13
22	1
23	16
24	-15
25	1
26	18
27	-17
28	1
29	20
30	-19
31	1
32	22
33	-21
34	1
35	24
36	-23
37	1
38	26
39	-25
40	1
41	28
42	-27
43	1
44	30
45	-29
46	1
47	32
48	-31
49	1
50	34
51	-33
52	1
53	36
54	-35
55	1
56	38
57	-37
58	1
59	40
60	-39

n	a(n)
1	1
2	2
3	-1
4	1
5	4
6	-3
7	1
8	6
9	-5
10	1
11	8
12	-7
13	1
14	10
15	-9
16	1
17	12
18	-11
19	1
20	14
21	-13
22	1
23	16
24	-15
25	1
26	18
27	-17
28	1
29	20
30	-19
31	1
32	22
33	-21
34	1
35	24
36	-23
37	1
38	26
39	-25
40	1
41	28
42	-27
43	1
44	30
45	-29
46	1
47	32
48	-31
49	1
50	34
51	-33
52	1
53	36
54	-35
55	1
56	38
57	-37
58	1
59	40
60	-39