A047820 - cp's OEIS frontend

A047820 Composite numbers that become prime after exactly 1 iteration of f(k) = sum of distinct prime factors of k.

n	a(n)
1	4
2	6
3	8
4	9
5	10
6	12
7	16
8	18
9	20
10	22
11	24
12	25
13	27
14	32
15	34
16	36
17	40
18	44
19	48
20	49
21	50
22	54
23	58
24	64
25	68
26	72
27	80
28	81
29	82
30	88
31	96
32	100
33	108
34	116
35	118
36	121
37	125
38	128
39	136
40	142
41	144
42	160
43	162
44	164
45	165
46	169
47	176
48	192
49	200
50	202
51	210
52	214
53	216
54	232
55	236
56	242
57	243
58	250
59	256
60	272

[4, 6, 8, 9, 10, 12, 16, 18, 20, 22, 24, 25, 27, 32, 34, 36, 40, 44, 48, 49, 50, 54, 58, 64, 68, 72, 80, 81, 82, 88, 96, 100, 108, 116, 118, 121, 125, 128, 136, 142, 144, 160, 162, 164, 165, 169, 176, 192, 200, 202, 210, 214, 216, 232, 236, 242, 243, 250, 256, 272]

cp's OEIS Frontend

A047820 Composite numbers that become prime after exactly 1 iteration of f(k) = sum of distinct prime factors of k.

Table of values

List of values

n	a(n)
1	4
2	6
3	8
4	9
5	10
6	12
7	16
8	18
9	20
10	22
11	24
12	25
13	27
14	32
15	34
16	36
17	40
18	44
19	48
20	49
21	50
22	54
23	58
24	64
25	68
26	72
27	80
28	81
29	82
30	88
31	96
32	100
33	108
34	116
35	118
36	121
37	125
38	128
39	136
40	142
41	144
42	160
43	162
44	164
45	165
46	169
47	176
48	192
49	200
50	202
51	210
52	214
53	216
54	232
55	236
56	242
57	243
58	250
59	256
60	272

n	a(n)
1	4
2	6
3	8
4	9
5	10
6	12
7	16
8	18
9	20
10	22
11	24
12	25
13	27
14	32
15	34
16	36
17	40
18	44
19	48
20	49
21	50
22	54
23	58
24	64
25	68
26	72
27	80
28	81
29	82
30	88
31	96
32	100
33	108
34	116
35	118
36	121
37	125
38	128
39	136
40	142
41	144
42	160
43	162
44	164
45	165
46	169
47	176
48	192
49	200
50	202
51	210
52	214
53	216
54	232
55	236
56	242
57	243
58	250
59	256
60	272

n	a(n)
1	4
2	6
3	8
4	9
5	10
6	12
7	16
8	18
9	20
10	22
11	24
12	25
13	27
14	32
15	34
16	36
17	40
18	44
19	48
20	49
21	50
22	54
23	58
24	64
25	68
26	72
27	80
28	81
29	82
30	88
31	96
32	100
33	108
34	116
35	118
36	121
37	125
38	128
39	136
40	142
41	144
42	160
43	162
44	164
45	165
46	169
47	176
48	192
49	200
50	202
51	210
52	214
53	216
54	232
55	236
56	242
57	243
58	250
59	256
60	272