A354346 - cp's OEIS frontend

A354346 a(n) = 2*n - A064989(sigma(sigma(A003961(n)))), where A003961 shifts the prime factorization one step towards larger primes, and A064989 shifts it back towards smaller primes.

n	a(n)
1	1
2	-1
3	4
4	3
5	4
6	6
7	9
8	4
9	17
10	0
11	20
12	14
13	4
14	-1
15	1
16	-53
17	24
18	31
19	32
20	10
21	-24
22	38
23	42
24	-10
25	47
26	-14
27	29
28	31
29	38
30	-53
31	56
32	39
33	61
34	10
35	50
36	67
37	72
38	56
39	63
40	-146
41	72
42	-136
43	57
44	78
45	84
46	80
47	88
48	-74
49	95
50	85
51	90
52	-6
53	96
54	-37
55	81
56	72
57	-205
58	38
59	116
60	-25
61	102
62	106
63	121
64	-413
65	-189
66	103
67	68
68	86
69	28
70	62
71	108
72	132
73	88
74	142
75	84

[1, -1, 4, 3, 4, 6, 9, 4, 17, 0, 20, 14, 4, -1, 1, -53, 24, 31, 32, 10, -24, 38, 42, -10, 47, -14, 29, 31, 38, -53, 56, 39, 61, 10, 50, 67, 72, 56, 63, -146, 72, -136, 57, 78, 84, 80, 88, -74, 95, 85, 90, -6, 96, -37, 81, 72, -205, 38, 116, -25, 102, 106, 121, -413, -189, 103, 68, 86, 28, 62, 108, 132, 88, 142, 84]

cp's OEIS Frontend

A354346 a(n) = 2*n - A064989(sigma(sigma(A003961(n)))), where A003961 shifts the prime factorization one step towards larger primes, and A064989 shifts it back towards smaller primes.

Table of values

List of values