Anaprimes

From Rosetta Code
Revision as of 00:48, 1 February 2023 by Thundergnat (talk | contribs) (New draft task and Raku example)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Anaprimes is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Anaprimes are prime numbers that are anagrams of each other; i.e. they use all of the same digits but in a different order.

Anaprimes are very common. There is an anagram group however, in each order of magnitude that contains more members than any other.


Task
  • Find prime numbers that are anagrams of each other.
  • Find the largest anagram group of prime numbers and display the count, and minimum and maximum members for prime numbers:
    • up to three digits long (before 1,000)
    • up to four digits long (before 10,000)
    • up to five digits long (before 100,000)
    • up to six digits long (before 1,000,000)


Stretch
  • Find the largest anagram group and display the count, and smallest and largest members for prime numbers:
    • up to seven digits long (before 10,000,000)
    • up to eight digits long (before 100,000,000)
    • up to nine digits long (before 1,000,000,000)
    • ???!


Related tasks


Raku

9 digit is slooow. I didn't have the patience for 10.

use Lingua::EN::Numbers;
use Math::Primesieve;

my $p = Math::Primesieve.new;

for 3 .. 9 {
    my $largest = $p.primes(10**($_-1), 10**$_).classify(*.comb.sort.join).max(+*.value).value;

    put "\nLargest group of anaprimes before {cardinal 10 ** $_}: {+$largest} members.";
    put 'First: ', ' Last: ' Z~ $largest[0, *-1];
}
Output:
Largest group of anaprimes before one thousand: 4 members.
First: 179  Last: 971

Largest group of anaprimes before ten thousand: 11 members.
First: 1237  Last: 7321

Largest group of anaprimes before one hundred thousand: 39 members.
First: 13789  Last: 98731

Largest group of anaprimes before one million: 148 members.
First: 123479  Last: 974213

Largest group of anaprimes before ten million: 731 members.
First: 1235789  Last: 9875321

Largest group of anaprimes before one hundred million: 4,333 members.
First: 12345769  Last: 97654321

Largest group of anaprimes before one billion: 26,519 members.
First: 102345697  Last: 976542103