Overview
A database with every combination of prime factors (2,3 and 7) that produce a multiplicative persistence > 2 in base 10 (that i've found so far).
Description
Multiple numbers may multiply to a common combination of prime factors, for example 277 and 772 both multiply to 98 (2*7*7). So to reduce search space we look for the combinations itself. For short a combination is written as 2^i * 3^j * 7^k.
Why no 5's?
5's are evil!
Test
I've missed a combination? Test it here and it will be automatically inserted in the database (if missing).
2^
A valid number between 0 and 10000 is required.
3^
A valid number between 0 and 10000 is required.
7^
A valid number between 0 and 10000 is required.
Persistence
The database
Count: 8787
Checked: i, j, k <= 2455
| Combination | Persistence |
|---|---|