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A124083
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Numbers k such that prime(k)!/prime(k)# + 1 is prime.
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1
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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1*2/2 +1 = 2 prime so a(1)=1 as 2=prime(1).
1*2*3/(2*3) +1 = 2 prime so a(2)=2 as 3=prime(2).
1*2*3*4*5/(2*3*5) +1 = 5 prime so a(3)=3 as 5=prime(3).
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PROG
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(PARI) isok(k) = isprime(prime(k)!/prod(i=1, k, prime(i)) + 1); \\ Michel Marcus, Sep 15 2019
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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