Composite numbers k with no single digit factors whose factors are all substrings of k: Difference between revisions
Content added Content deleted
(Created Nim solution.) |
(Set the number of results to 20 as required.) |
||
| Line 353: | Line 353: | ||
We use a sieve to build a list of prime factors. This is more efficient than computing the list of prime factors on the fly. |
We use a sieve to build a list of prime factors. This is more efficient than computing the list of prime factors on the fly. |
||
To find the |
To find the 20 first elements of the sequence, the program takes less than 10 seconds on an Intel Core I5-8250U 4×1.6GHz. |
||
<syntaxhighlight lang="Nim">import std/[strformat, strutils] |
<syntaxhighlight lang="Nim">import std/[strformat, strutils] |
||
| Line 372: | Line 372: | ||
primeFactors(k).add n |
primeFactors(k).add n |
||
const N = |
const N = 20 # Number of results. |
||
var n = 11 * 11 |
var n = 11 * 11 |
||
var count = 0 |
var count = 0 |
||
| Line 407: | Line 407: | ||
19: 19_173_071 |
19: 19_173_071 |
||
20: 28_118_827 |
20: 28_118_827 |
||
21: 31_373_137 |
|||
22: 47_458_321 |
|||
23: 55_251_877 |
|||
24: 62_499_251 |
|||
25: 79_710_361 |
|||
</pre> |
</pre> |
||