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A248892
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Primes p of the form 4m^2+1 such that q=4p^2+1, r=4q^2+1 and s=4r^2+1 are all prime.
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0
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1565891838737, 1985917919077, 2060476510097, 5590084720897, 39623323626437, 94860314619877, 114027286862737, 115071875848337, 117140013119377, 136739205150917, 246382184192357, 254109295929637, 265883157493777, 340055949647237, 378534223873937
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OFFSET
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1,1
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COMMENTS
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Corresponding values of k: 625678,704613,717718,1182168,3147353,4869813,5339178,5363578,5411562,5846777,7848283,7970403,8152962,9220303,9727978.
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LINKS
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Table of n, a(n) for n=1..15.
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MATHEMATICA
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apQ[p_]:=Module[{q=4p^2+1, r}, r=4q^2+1; AllTrue[{p, q, r, 4r^2+1}, PrimeQ]]; Select[ 4*Range[ 10^7]^2+1, apQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 28 2019 *)
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CROSSREFS
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Subsequence of A248887. Cf. A001912, A121326, A121834, A248887.
Sequence in context: A288276 A246251 A320943 * A172799 A015422 A289148
Adjacent sequences: A248889 A248890 A248891 * A248893 A248894 A248895
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov, Mar 05 2015
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STATUS
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approved
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