cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A037273 Number of steps to reach a prime under "replace n with concatenation of its prime factors", or -1 if no prime is ever reached.

Table of values

n a(n)
1 -1
2 0
3 0
4 2
5 0
6 1
7 0
8 13
9 2
10 4
11 0
12 1
13 0
14 5
15 4
16 4
17 0
18 1
19 0
20 15
21 1
22 1
23 0
24 2
25 3
26 4
27 4
28 1
29 0
30 2
31 0
32 2
33 1
34 5
35 3
36 2
37 0
38 2
39 1
40 9
41 0
42 2
43 0
44 9
45 6
46 1
47 0
48 15

List of values

[-1, 0, 0, 2, 0, 1, 0, 13, 2, 4, 0, 1, 0, 5, 4, 4, 0, 1, 0, 15, 1, 1, 0, 2, 3, 4, 4, 1, 0, 2, 0, 2, 1, 5, 3, 2, 0, 2, 1, 9, 0, 2, 0, 9, 6, 1, 0, 15]