9 lines
213 B
Ruby
9 lines
213 B
Ruby
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require "prime"
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additive_primes = Prime.lazy.select{|prime| prime.digits.sum.prime? }
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N = 500
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res = additive_primes.take_while{|n| n < N}.to_a
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puts res.join(" ")
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puts "\n#{res.size} additive primes below #{N}."
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