A167232 - cp's OEIS frontend

A167232 a(n) is the number obtained by writing out numbers from 1 to n and placing an alternate + and - minus sign between successive digits and evaluating the expression written.

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

[1, -1, 2, -2, 3, -3, 4, -4, 5, 4, 4, 3, 4, 3, 5, 4, 7, 6, 10, 9, 14, 13, 19, 18, 25, 24, 32, 31, 40, 38, 38, 36, 37, 35, 37, 35, 38, 36, 40, 38, 43, 41, 47, 45, 52, 50, 58, 56, 65, 62, 62, 59, 60, 57, 59, 56, 59, 56, 60, 57, 62, 59, 65, 62, 69, 66, 74, 71, 80, 76, 76, 72, 73, 69]

cp's OEIS Frontend

A167232 a(n) is the number obtained by writing out numbers from 1 to n and placing an alternate + and - minus sign between successive digits and evaluating the expression written.

Table of values

List of values

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

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

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