17 lines
382 B
Ruby
17 lines
382 B
Ruby
require "prime"
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smarandache = Enumerator.new do|y|
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prime_digits = [2,3,5,7]
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prime_digits.each{|pr| y << pr} # yield the below-tens
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(1..).each do |n|
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prime_digits.repeated_permutation(n).each do |perm|
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c = perm.join.to_i * 10
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y << c + 3 if (c+3).prime?
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y << c + 7 if (c+7).prime?
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end
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end
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end
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seq = smarandache.take(100)
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p seq.first(25)
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p seq.last
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