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A182121
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Primes p such that the sum of both three and five consecutive primes starting with p is prime.
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3
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5, 7, 11, 19, 29, 31, 53, 67, 79, 109, 149, 157, 163, 211, 229, 311, 349, 379, 401, 409, 449, 467, 653, 757, 809, 839, 857, 863, 883, 983, 997, 1033, 1087, 1103, 1187, 1193, 1289, 1301, 1303, 1409, 1481, 1523, 1553, 1637, 1663, 1669, 1709, 1951, 1973
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OFFSET
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1,1
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LINKS
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EXAMPLE
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5 is in the sequence because 5 + 7 + 11 = 23 is prime and 5 + 7 + 11 + 13 + 17 = 53 is also prime.
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MATHEMATICA
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cpQ[n_]:=Module[{ppi=PrimePi[n], cnsc}, cnsc=Prime[Range[ppi, ppi+4]]; And@@ PrimeQ[ {Total[cnsc], Total[Take[cnsc, 3]]}]]; Select[Prime[Range[300]], cpQ] (* Harvey P. Dale, Mar 28 2013 *)
Select[Partition[Prime[Range[500]], 5, 1], AllTrue[{Total[Take[#, 3]], Total[#]}, PrimeQ]&][[;; , 1]] (* Harvey P. Dale, Feb 11 2024 *)
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PROG
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(PARI) {a=2; b=3; c=5; d=7; e=11; for(n=1, 300, s=a+b+c+d+e;
if(isprime(s)&&isprime(a+b+c), print1(a", ")); a=b; b=c; c=d; d=e; e=nextprime(e+2))}
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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