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A231235
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Primes q of the form p^2 + 4 (p prime) such that r = q^2 + 4, s = r^2 + 4 and t = s^2 + 4 are all prime.
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1
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93738231893, 2365771484804813, 4185535280578373, 4658429282719973, 7706774555568173, 7711174427503853, 25756066576859093, 65522912397466973, 80107252841869013, 105371595617867573, 130831138562692133, 174460360753737533, 201928181545454813, 204300010667474573
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OFFSET
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1,1
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COMMENTS
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The next iteration is impossible: t^2 + 4 is divisible by 13.
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LINKS
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MATHEMATICA
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extnd[p_]:=NestList[#^2+4&, p, 4]; #^2+4&/@Select[Prime[ Range[ 452*10^6]], AllTrue[Rest[extnd[#]], PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 06 2021 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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