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A240596
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Primes of the form p*q*r + 2 where p, q and r are consecutive primes.
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5
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107, 4201, 18181981, 29884303, 72147193, 81927499, 208506511, 383148631, 402473443, 1106558899, 1391119621, 1459314919, 1498299289, 1945171369, 4593570199, 7908301729, 8052037969, 9970592521, 10594343761, 11304695329, 14119758703, 15111907009, 23157107803
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OFFSET
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1,1
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COMMENTS
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All the terms in the sequence, except a(1), are congruent to 1 mod 6.
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LINKS
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EXAMPLE
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107 is prime and appears in the sequence because 107 = (3*5*7)+2.
4201 is prime and appears in the sequence because 4201 = (13*17*19)+2.
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MAPLE
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KD := proc() local a, b; a:=ithprime(n)*ithprime(n+1)*ithprime(n+2); b:=a+2; if isprime(b) then RETURN (b); fi; end: seq(KD(), n=1..1000);
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MATHEMATICA
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Select[Table[Prime[k]*Prime[k+1]*Prime[k+2]+2, {k, 1, 300}], PrimeQ]
Select[Times@@@Partition[Prime[Range[600]], 3, 1]+2, PrimeQ] (* Harvey P. Dale, Nov 21 2018 *)
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PROG
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(PARI) s=[]; for(k=1, 1000, t=prime(k)*prime(k+1)*prime(k+2)+2; if(isprime(t), s=concat(s, t))); s \\ Colin Barker, Apr 09 2014
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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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