A377984 - cp's OEIS frontend

A377984 a(n) = 2*sigma(n) - A003961(n), where sigma is the sum of divisors function and A003961 is fully multiplicative function with a(prime(i)) = prime(i+1).

n	a(n)
1	1
2	3
3	3
4	5
5	5
6	9
7	5
8	3
9	1
10	15
11	11
12	11
13	11
14	15
15	13
16	-19
17	17
18	3
19	17
20	21
21	9
22	33
23	19
24	-15
25	13
26	33
27	-45
28	13
29	29
30	39
31	27
32	-117
33	31
34	51
35	19
36	-43
37	35
38	51
39	27
40	-9
41	41
42	27
43	41
44	51
45	-19
46	57
47	43
48	-157
49	-7
50	39
51	49
52	43
53	49
54	-135
55	53
56	-57
57	45
58	87
59	59
60	21
61	57
62	81
63	-67
64	-475
65	49
66	93
67	65
68	81
69	47
70	57
71	71
72	-285
73	69
74	105
75	3
76	73
77	49
78	81

[1, 3, 3, 5, 5, 9, 5, 3, 1, 15, 11, 11, 11, 15, 13, -19, 17, 3, 17, 21, 9, 33, 19, -15, 13, 33, -45, 13, 29, 39, 27, -117, 31, 51, 19, -43, 35, 51, 27, -9, 41, 27, 41, 51, -19, 57, 43, -157, -7, 39, 49, 43, 49, -135, 53, -57, 45, 87, 59, 21, 57, 81, -67, -475, 49, 93, 65, 81, 47, 57, 71, -285, 69, 105, 3, 73, 49, 81]

cp's OEIS Frontend

A377984 a(n) = 2*sigma(n) - A003961(n), where sigma is the sum of divisors function and A003961 is fully multiplicative function with a(prime(i)) = prime(i+1).

Table of values

List of values