A336760 - cp's OEIS frontend

A336760 a(0) = 0; for n > 0, a(n) = a(n-1) - tau(n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + tau(n), where tau(n) is the number of divisors of n.

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

[0, 1, 3, 5, 2, 4, 8, 6, 10, 7, 11, 9, 15, 13, 17, 21, 16, 14, 20, 18, 12, 16, 20, 22, 30, 27, 23, 19, 25, 27, 35, 33, 39, 43, 47, 51, 42, 40, 36, 32, 24, 26, 34, 36, 42, 48, 44, 46, 56, 53, 59, 55, 49, 51, 59, 63, 71, 67, 71, 69, 57, 59, 63, 69, 62, 58, 50, 52, 58, 54, 62, 60, 72, 70, 66, 72]

cp's OEIS Frontend

A336760 a(0) = 0; for n > 0, a(n) = a(n-1) - tau(n) if nonnegative and not already in the sequence, otherwise a(n) = a(n-1) + tau(n), where tau(n) is the number of divisors of n.

Table of values

List of values

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

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

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