A107758 - cp's OEIS frontend

A107758 (+2)Sigma(n): If n = Product p_i^r_i then a(n) = Product (2 + Sum p_i^s_i, s_i=1 to r_i) = Product (1 + (p_i^(r_i+1)-1)/(p_i-1)), a(1) = 1.

n	a(n)
1	1
2	4
3	5
4	8
5	7
6	20
7	9
8	16
9	14
10	28
11	13
12	40
13	15
14	36
15	35
16	32
17	19
18	56
19	21
20	56
21	45
22	52
23	25
24	80
25	32
26	60
27	41
28	72
29	31
30	140
31	33
32	64
33	65
34	76
35	63
36	112
37	39
38	84
39	75
40	112
41	43
42	180
43	45
44	104
45	98
46	100
47	49
48	160
49	58
50	128
51	95
52	120
53	55
54	164

[1, 4, 5, 8, 7, 20, 9, 16, 14, 28, 13, 40, 15, 36, 35, 32, 19, 56, 21, 56, 45, 52, 25, 80, 32, 60, 41, 72, 31, 140, 33, 64, 65, 76, 63, 112, 39, 84, 75, 112, 43, 180, 45, 104, 98, 100, 49, 160, 58, 128, 95, 120, 55, 164]

cp's OEIS Frontend

A107758 (+2)Sigma(n): If n = Product p_i^r_i then a(n) = Product (2 + Sum p_i^s_i, s_i=1 to r_i) = Product (1 + (p_i^(r_i+1)-1)/(p_i-1)), a(1) = 1.

Table of values

List of values

n	a(n)
1	1
2	4
3	5
4	8
5	7
6	20
7	9
8	16
9	14
10	28
11	13
12	40
13	15
14	36
15	35
16	32
17	19
18	56
19	21
20	56
21	45
22	52
23	25
24	80
25	32
26	60
27	41
28	72
29	31
30	140
31	33
32	64
33	65
34	76
35	63
36	112
37	39
38	84
39	75
40	112
41	43
42	180
43	45
44	104
45	98
46	100
47	49
48	160
49	58
50	128
51	95
52	120
53	55
54	164

n	a(n)
1	1
2	4
3	5
4	8
5	7
6	20
7	9
8	16
9	14
10	28
11	13
12	40
13	15
14	36
15	35
16	32
17	19
18	56
19	21
20	56
21	45
22	52
23	25
24	80
25	32
26	60
27	41
28	72
29	31
30	140
31	33
32	64
33	65
34	76
35	63
36	112
37	39
38	84
39	75
40	112
41	43
42	180
43	45
44	104
45	98
46	100
47	49
48	160
49	58
50	128
51	95
52	120
53	55
54	164

n	a(n)
1	1
2	4
3	5
4	8
5	7
6	20
7	9
8	16
9	14
10	28
11	13
12	40
13	15
14	36
15	35
16	32
17	19
18	56
19	21
20	56
21	45
22	52
23	25
24	80
25	32
26	60
27	41
28	72
29	31
30	140
31	33
32	64
33	65
34	76
35	63
36	112
37	39
38	84
39	75
40	112
41	43
42	180
43	45
44	104
45	98
46	100
47	49
48	160
49	58
50	128
51	95
52	120
53	55
54	164