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A063898
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Smallest k > 0 such that k + F_n are all primes, where F_n is the n-th Fermat number.
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0
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OFFSET
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0,1
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COMMENTS
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Is this sequence finite?
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LINKS
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EXAMPLE
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For j=3 a(3)=2 because 257+2, 17+2, 5+2, 3+2 are all primes.
For j=4 a(4)=14 because 65537+14, 257+14, 17+14, 5+14, 3+14 are all primes.
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PROG
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(PARI) okprimep(mink, vecf) = {for (i=1, #vecf, if (! isprime(mink + vecf[i]), return (0)); ); return (1); }
a(n) = {mink = 1; vecf = vector(n+1, i, 2^(2^(i-1)) + 1); while (! okprimep(mink, vecf), mink++); mink; } \\ Michel Marcus, Sep 28 2013
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CROSSREFS
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KEYWORD
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hard,more,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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