A348689 - cp's OEIS frontend

A348689 a(n) = sigma(n) + sigma(n+1) - sigma(n+2), where sigma is the sum of divisors.

n	a(n)
1	0
2	0
3	5
4	1
5	10
6	5
7	10
8	10
9	19
10	2
11	26
12	18
13	14
14	17
15	37
16	10
17	37
18	17
19	30
20	38
21	44
22	0
23	53
24	49
25	33
26	26
27	66
28	14
29	70
30	41
31	47
32	57
33	54
34	11
35	101
36	69
37	42
38	26
39	104
40	36
41	94
42	56
43	50
44	90
45	102
46	-4
47	115
48	88
49	78
50	67
51	116
52	32
53	102
54	72
55	112
56	110
57	110
58	-18
59	166
60	134
61	54
62	73
63	147
64	67
65	160
66	86
67	98
68	78
69	168
70	21

[0, 0, 5, 1, 10, 5, 10, 10, 19, 2, 26, 18, 14, 17, 37, 10, 37, 17, 30, 38, 44, 0, 53, 49, 33, 26, 66, 14, 70, 41, 47, 57, 54, 11, 101, 69, 42, 26, 104, 36, 94, 56, 50, 90, 102, -4, 115, 88, 78, 67, 116, 32, 102, 72, 112, 110, 110, -18, 166, 134, 54, 73, 147, 67, 160, 86, 98, 78, 168, 21]

cp's OEIS Frontend

A348689 a(n) = sigma(n) + sigma(n+1) - sigma(n+2), where sigma is the sum of divisors.

Table of values

List of values

n	a(n)
1	0
2	0
3	5
4	1
5	10
6	5
7	10
8	10
9	19
10	2
11	26
12	18
13	14
14	17
15	37
16	10
17	37
18	17
19	30
20	38
21	44
22	0
23	53
24	49
25	33
26	26
27	66
28	14
29	70
30	41
31	47
32	57
33	54
34	11
35	101
36	69
37	42
38	26
39	104
40	36
41	94
42	56
43	50
44	90
45	102
46	-4
47	115
48	88
49	78
50	67
51	116
52	32
53	102
54	72
55	112
56	110
57	110
58	-18
59	166
60	134
61	54
62	73
63	147
64	67
65	160
66	86
67	98
68	78
69	168
70	21

n	a(n)
1	0
2	0
3	5
4	1
5	10
6	5
7	10
8	10
9	19
10	2
11	26
12	18
13	14
14	17
15	37
16	10
17	37
18	17
19	30
20	38
21	44
22	0
23	53
24	49
25	33
26	26
27	66
28	14
29	70
30	41
31	47
32	57
33	54
34	11
35	101
36	69
37	42
38	26
39	104
40	36
41	94
42	56
43	50
44	90
45	102
46	-4
47	115
48	88
49	78
50	67
51	116
52	32
53	102
54	72
55	112
56	110
57	110
58	-18
59	166
60	134
61	54
62	73
63	147
64	67
65	160
66	86
67	98
68	78
69	168
70	21

n	a(n)
1	0
2	0
3	5
4	1
5	10
6	5
7	10
8	10
9	19
10	2
11	26
12	18
13	14
14	17
15	37
16	10
17	37
18	17
19	30
20	38
21	44
22	0
23	53
24	49
25	33
26	26
27	66
28	14
29	70
30	41
31	47
32	57
33	54
34	11
35	101
36	69
37	42
38	26
39	104
40	36
41	94
42	56
43	50
44	90
45	102
46	-4
47	115
48	88
49	78
50	67
51	116
52	32
53	102
54	72
55	112
56	110
57	110
58	-18
59	166
60	134
61	54
62	73
63	147
64	67
65	160
66	86
67	98
68	78
69	168
70	21