Anaprimes: Difference between revisions
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Largest group of anaprimes before one billion: 26,519 members.
First: 102345697 Last: 976542103</pre>
=={{header|Ruby}}==
9 digit takes about 4 minutes (not done here). Could use something like Raku's Allmax.
<syntaxhighlight lang="ruby" line>require 'prime'
upto = 100_000_000
h = Hash.new {|hash, key| hash[key] = []}
Prime.each(upto) do |pr|
h[pr.digits.sort] << pr
end
(3..(upto.digits.size-1)).each do |num_digits|
group = h.select {|k,v| k.size == num_digits}
sizes = group.values.group_by(&:size)
max = sizes.keys.max
maxes = sizes[max]
puts "Anaprime groups of #{num_digits} digits: #{maxes.size} ha#{maxes.size == 1 ? "s" : "ve"} #{max} primes."
maxes.each{|group| puts " First: #{group.first} Last: #{group.last}"}
end
</syntaxhighlight>
{{out}}
<pre>Anaprime groups of 3 digits: 3 have 4 primes.
First: 149 Last: 941
First: 179 Last: 971
First: 379 Last: 937
Anaprime groups of 4 digits: 2 have 11 primes.
First: 1237 Last: 7321
First: 1279 Last: 9721
Anaprime groups of 5 digits: 1 has 39 primes.
First: 13789 Last: 98731
Anaprime groups of 6 digits: 1 has 148 primes.
First: 123479 Last: 974213
Anaprime groups of 7 digits: 1 has 731 primes.
First: 1235789 Last: 9875321
Anaprime groups of 8 digits: 1 has 4333 primes.
First: 12345769 Last: 97654321</pre>
=={{header|Wren}}==
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