A067600 - cp's OEIS frontend

A067600 Numbers n such that f(n) and f(f(n)) are prime, where f(k) = decimal encoding of the prime factorization of k.

n	a(n)
1	3
2	20
3	69
4	171
5	174
6	267
7	333
8	360
9	372
10	448
11	537
12	665
13	666
14	776
15	820
16	824
17	855
18	873
19	1016
20	1125
21	1330
22	1413
23	1450
24	1532
25	1604
26	1689
27	1796
28	1860
29	1899
30	1959
31	2048
32	2068
33	2184
34	2319
35	2449
36	2620
37	2658
38	2670
39	2804
40	2823
41	3139
42	3210
43	3342
44	3464
45	3552
46	3589

[3, 20, 69, 171, 174, 267, 333, 360, 372, 448, 537, 665, 666, 776, 820, 824, 855, 873, 1016, 1125, 1330, 1413, 1450, 1532, 1604, 1689, 1796, 1860, 1899, 1959, 2048, 2068, 2184, 2319, 2449, 2620, 2658, 2670, 2804, 2823, 3139, 3210, 3342, 3464, 3552, 3589]

cp's OEIS Frontend

A067600 Numbers n such that f(n) and f(f(n)) are prime, where f(k) = decimal encoding of the prime factorization of k.

Table of values

List of values